diff --git a/modules/payment/commerce_payment.module b/modules/payment/commerce_payment.module
index ba5bc5b3..40ce5242 100644
--- a/modules/payment/commerce_payment.module
+++ b/modules/payment/commerce_payment.module
@@ -5,6 +5,7 @@
  * Provides payment functionality.
  */
 
+use Drupal\commerce_order\Entity\OrderInterface;
 use Drupal\commerce_payment\Plugin\Commerce\PaymentGateway\HasPaymentInstructionsInterface;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Entity\EntityTypeInterface;
diff --git a/modules/payment/commerce_payment.services.yml b/modules/payment/commerce_payment.services.yml
index 8dfba4f7..d26f52ff 100644
--- a/modules/payment/commerce_payment.services.yml
+++ b/modules/payment/commerce_payment.services.yml
@@ -26,6 +26,12 @@ services:
     tags:
       - { name: event_subscriber }
 
+  commerce_payment.kernel_subscriber:
+    class: Drupal\commerce_payment\EventSubscriber\KernelSubscriber
+    arguments: ['@commerce_payment.order_updater']
+    tags:
+    - { name: event_subscriber }
+
   commerce_payment.order_assign_subscriber:
     class: Drupal\commerce_payment\EventSubscriber\OrderAssignSubscriber
     tags:
@@ -40,6 +46,12 @@ services:
     class: Drupal\commerce_payment\PaymentOptionsBuilder
     arguments: ['@entity_type.manager', '@string_translation']
 
-  commerce_payment.order_manager:
-    class: Drupal\commerce_payment\PaymentOrderManager
+  commerce_payment.order_processor:
+    class: Drupal\commerce_payment\PaymentOrderProcessor
+    arguments: ['@commerce_payment.order_updater']
+    tags:
+    - { name: commerce_order.order_processor, priority: 400, adjustment_type: tax }
+
+  commerce_payment.order_updater:
+    class: Drupal\commerce_payment\PaymentOrderUpdater
     arguments: ['@entity_type.manager']
diff --git a/modules/payment/src/Entity/Payment.php b/modules/payment/src/Entity/Payment.php
index 9d26d7d6..f6b38614 100644
--- a/modules/payment/src/Entity/Payment.php
+++ b/modules/payment/src/Entity/Payment.php
@@ -318,9 +318,10 @@ class Payment extends ContentEntityBase implements PaymentInterface {
    * {@inheritdoc}
    */
   public function postSave(EntityStorageInterface $storage, $update = TRUE) {
-    if ($this->isCompleted()) {
-      $payment_order_manager = \Drupal::service('commerce_payment.order_manager');
-      $payment_order_manager->updateTotalPaid($this->getOrder());
+    $order = $this->getOrder();
+    if ($order && $this->isCompleted()) {
+      $payment_order_updater = \Drupal::service('commerce_payment.order_updater');
+      $payment_order_updater->requestUpdate($order);
     }
   }
 
@@ -330,15 +331,11 @@ class Payment extends ContentEntityBase implements PaymentInterface {
   public static function postDelete(EntityStorageInterface $storage, array $entities) {
     parent::postDelete($storage, $entities);
 
-    // Multiple payments might reference the same order, make sure that each
-    // order is only updated once.
-    $orders = [];
+    $payment_order_updater = \Drupal::service('commerce_payment.order_updater');
     foreach ($entities as $entity) {
-      $orders[$entity->getOrderId()] = $entity->getOrder();
-    }
-    $payment_order_manager = \Drupal::service('commerce_payment.order_manager');
-    foreach ($orders as $order) {
-      $payment_order_manager->updateTotalPaid($order);
+      if ($order = $entity->getOrder()) {
+        $payment_order_updater->requestUpdate($order);
+      }
     }
   }
 
diff --git a/modules/payment/src/EventSubscriber/KernelSubscriber.php b/modules/payment/src/EventSubscriber/KernelSubscriber.php
new file mode 100644
index 00000000..69dc3141
--- /dev/null
+++ b/modules/payment/src/EventSubscriber/KernelSubscriber.php
@@ -0,0 +1,48 @@
+<?php
+
+namespace Drupal\commerce_payment\EventSubscriber;
+
+use Drupal\commerce_payment\PaymentOrderUpdaterInterface;
+use Symfony\Component\HttpKernel\KernelEvents;
+use Symfony\Component\HttpKernel\Event\PostResponseEvent;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+class KernelSubscriber implements EventSubscriberInterface {
+
+  /**
+   * The payment order updater.
+   *
+   * @var \Drupal\commerce_payment\PaymentOrderUpdaterInterface
+   */
+  protected $paymentOrderUpdater;
+
+  /**
+   * Constructs a new KernelSubscriber instance.
+   *
+   * @param \Drupal\commerce_payment\PaymentOrderUpdaterInterface $payment_order_updater
+   *   The payment order updater.
+   */
+  public function __construct(PaymentOrderUpdaterInterface $payment_order_updater) {
+    $this->paymentOrderUpdater = $payment_order_updater;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    return [
+      KernelEvents::TERMINATE => ['onTerminate', 400],
+    ];
+  }
+
+  /**
+   * Updates all remaining orders with pending updates.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\PostResponseEvent $event
+   *   The event.
+   */
+  public function onTerminate(PostResponseEvent $event) {
+    $this->paymentOrderUpdater->updateOrders();
+  }
+
+}
diff --git a/modules/payment/src/PaymentOrderManagerInterface.php b/modules/payment/src/PaymentOrderManagerInterface.php
deleted file mode 100644
index 4761960b..00000000
--- a/modules/payment/src/PaymentOrderManagerInterface.php
+++ /dev/null
@@ -1,22 +0,0 @@
-<?php
-
-namespace Drupal\commerce_payment;
-
-use Drupal\commerce_order\Entity\OrderInterface;
-
-/**
- * Updates orders based on payment information.
- */
-interface PaymentOrderManagerInterface {
-
-  /**
-   * Recalculates the total paid price for the given order.
-   *
-   * The order will be saved if the total paid price has changed.
-   *
-   * @param \Drupal\commerce_order\Entity\OrderInterface $order
-   *   The order.
-   */
-  public function updateTotalPaid(OrderInterface $order);
-
-}
diff --git a/modules/payment/src/PaymentOrderProcessor.php b/modules/payment/src/PaymentOrderProcessor.php
new file mode 100644
index 00000000..34c3559a
--- /dev/null
+++ b/modules/payment/src/PaymentOrderProcessor.php
@@ -0,0 +1,39 @@
+<?php
+
+namespace Drupal\commerce_payment;
+
+use Drupal\commerce_order\Entity\OrderInterface;
+use Drupal\commerce_order\OrderProcessorInterface;
+
+/**
+ * Recalculates the order's total_paid field.
+ */
+class PaymentOrderProcessor implements OrderProcessorInterface {
+
+  /**
+   * The payment order updater.
+   *
+   * @var \Drupal\commerce_payment\PaymentOrderUpdaterInterface
+   */
+  protected $paymentOrderUpdater;
+
+  /**
+   * Constructs a new PaymentOrderProcessor instance.
+   *
+   * @param \Drupal\commerce_payment\PaymentOrderUpdaterInterface $payment_order_updater
+   *   The order update manager.
+   */
+  public function __construct(PaymentOrderUpdaterInterface $payment_order_updater) {
+    $this->paymentOrderUpdater = $payment_order_updater;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function process(OrderInterface $order) {
+    if ($this->paymentOrderUpdater->needsUpdate($order)) {
+      $this->paymentOrderUpdater->updateOrder($order);
+    }
+  }
+
+}
diff --git a/modules/payment/src/PaymentOrderManager.php b/modules/payment/src/PaymentOrderUpdater.php
similarity index 53%
rename from modules/payment/src/PaymentOrderManager.php
rename to modules/payment/src/PaymentOrderUpdater.php
index 25417664..851d44d9 100644
--- a/modules/payment/src/PaymentOrderManager.php
+++ b/modules/payment/src/PaymentOrderUpdater.php
@@ -6,7 +6,14 @@ use Drupal\commerce_order\Entity\OrderInterface;
 use Drupal\commerce_price\Price;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 
-class PaymentOrderManager implements PaymentOrderManagerInterface {
+class PaymentOrderUpdater implements PaymentOrderUpdaterInterface {
+
+  /**
+   * The order storage.
+   *
+   * @var \Drupal\Core\Entity\EntityStorageInterface
+   */
+  protected $orderStorage;
 
   /**
    * The payment storage.
@@ -16,19 +23,54 @@ class PaymentOrderManager implements PaymentOrderManagerInterface {
   protected $paymentStorage;
 
   /**
-   * Constructs a new PaymentOrderManager object.
+   * The order IDs that need updating.
+   *
+   * @var int[]
+   */
+  protected $updateList = [];
+
+  /**
+   * Constructs a new PaymentOrderUpdater object.
    *
    * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
    *   The entity type manager.
    */
   public function __construct(EntityTypeManagerInterface $entity_type_manager) {
+    $this->orderStorage = $entity_type_manager->getStorage('commerce_order');
     $this->paymentStorage = $entity_type_manager->getStorage('commerce_payment');
   }
 
   /**
    * {@inheritdoc}
    */
-  public function updateTotalPaid(OrderInterface $order) {
+  public function requestUpdate(OrderInterface $order) {
+    $this->updateList[$order->id()] = $order->id();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function needsUpdate(OrderInterface $order) {
+    return !$order->isNew() && isset($this->updateList[$order->id()]);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function updateOrders() {
+    if (!empty($this->updateList)) {
+      /** @var \Drupal\commerce_order\Entity\OrderInterface[] $orders */
+      $orders = $this->orderStorage->loadMultiple($this->updateList);
+      foreach ($orders as $order) {
+        $this->updateOrder($order, TRUE);
+      }
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function updateOrder(OrderInterface $order, $save_order = FALSE) {
     $previous_total = $order->getTotalPaid();
     if (!$previous_total) {
       // A NULL total indicates an order that doesn't have any items yet.
@@ -47,8 +89,12 @@ class PaymentOrderManager implements PaymentOrderManagerInterface {
 
     if (!$previous_total->equals($new_total)) {
       $order->setTotalPaid($new_total);
-      $order->save();
+      if ($save_order) {
+        $order->save();
+      }
     }
+
+    unset($this->updateList[$order->id()]);
   }
 
 }
diff --git a/modules/payment/src/PaymentOrderUpdaterInterface.php b/modules/payment/src/PaymentOrderUpdaterInterface.php
new file mode 100644
index 00000000..2a53dcdb
--- /dev/null
+++ b/modules/payment/src/PaymentOrderUpdaterInterface.php
@@ -0,0 +1,64 @@
+<?php
+
+namespace Drupal\commerce_payment;
+
+use Drupal\commerce_order\Entity\OrderInterface;
+
+/**
+ * Updates orders based on payment information.
+ *
+ * When a payment is completed or refunded, the parent order's total_paid
+ * field must be recalculated.
+ *
+ * If the payment tries to update the parent order right away, it might
+ * generate a conflict, due to the order being edited elsewhere
+ * (e.g., a payment gateway's onReturn() method creating a payment, and
+ * then saving its own copy of the order). To avoid this problem, the updater
+ * allows requesting an update, which is then applied on the next order save.
+ * Any orders not saved by the end of the request will be saved when the
+ * KernelSubscriber calls the updater for final updates.
+ *
+ * @see \Drupal\commerce_payment\PaymentOrderProcessor
+ * @see \Drupal\commerce_payment\EventSubscriber\KernelSubscriber
+ */
+interface PaymentOrderUpdaterInterface {
+
+  /**
+   * Requests an update of the given order.
+   *
+   * @param \Drupal\commerce_order\Entity\OrderInterface $order
+   *   The order.
+   */
+  public function requestUpdate(OrderInterface $order);
+
+  /**
+   * Checks whether the given order needs to be updated.
+   *
+   * @param \Drupal\commerce_order\Entity\OrderInterface $order
+   *   The order.
+   *
+   * @return bool
+   *   TRUE if an update was requested, FALSE otherwise.
+   */
+  public function needsUpdate(OrderInterface $order);
+
+  /**
+   * Updates and saves all relevant orders.
+   */
+  public function updateOrders();
+
+  /**
+   * Updates the given order.
+   *
+   * The order's total_paid field will be recalculated to reflect the
+   * current payment total.
+   *
+   * @param \Drupal\commerce_order\Entity\OrderInterface $order
+   *   The order.
+   * @param bool $save_order
+   *   Whether the order should be saved after the update. Always skipped
+   *   if the total_paid field hasn't changed.
+   */
+  public function updateOrder(OrderInterface $order, $save_order = FALSE);
+
+}
diff --git a/modules/payment/tests/modules/commerce_payment_test/config/schema/commerce_payment_test.schema.yml b/modules/payment/tests/modules/commerce_payment_test/config/schema/commerce_payment_test.schema.yml
index cee53b9c..265ef021 100644
--- a/modules/payment/tests/modules/commerce_payment_test/config/schema/commerce_payment_test.schema.yml
+++ b/modules/payment/tests/modules/commerce_payment_test/config/schema/commerce_payment_test.schema.yml
@@ -1,3 +1,10 @@
+commerce_payment.commerce_payment_gateway.plugin.test_offsite:
+  type: commerce_payment_gateway_configuration
+  mapping:
+    redirect_method:
+      type: string
+      label: 'Redirect method'
+
 commerce_payment.commerce_payment_gateway.plugin.test_onsite:
   type: commerce_payment_gateway_configuration
   mapping:
diff --git a/modules/payment/tests/modules/commerce_payment_test/src/Plugin/Commerce/PaymentGateway/TestOffsite.php b/modules/payment/tests/modules/commerce_payment_test/src/Plugin/Commerce/PaymentGateway/TestOffsite.php
new file mode 100644
index 00000000..57d69309
--- /dev/null
+++ b/modules/payment/tests/modules/commerce_payment_test/src/Plugin/Commerce/PaymentGateway/TestOffsite.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace Drupal\commerce_payment_test\Plugin\Commerce\PaymentGateway;
+
+use Drupal\commerce_order\Entity\OrderInterface;
+use Drupal\commerce_payment_example\Plugin\Commerce\PaymentGateway\OffsiteRedirect;
+use Symfony\Component\HttpFoundation\Request;
+
+/**
+ * Provides the Test off-site payment gateway.
+ *
+ * This is a copy of example_offsite_redirect with additional logic around
+ * order data usage.
+ *
+ * @CommercePaymentGateway(
+ *   id = "test_offsite",
+ *   label = "Test (Off-site redirect)",
+ *   display_label = "Test",
+ *   forms = {
+ *     "offsite-payment" = "Drupal\commerce_payment_example\PluginForm\OffsiteRedirect\PaymentOffsiteForm",
+ *   },
+ *   payment_method_types = {"credit_card"},
+ *   credit_card_types = {
+ *     "amex", "dinersclub", "discover", "jcb", "maestro", "mastercard", "visa",
+ *   },
+ * )
+ */
+class TestOffsite extends OffsiteRedirect {
+
+  /**
+   * {@inheritdoc}
+   *
+   * Adds data to the order and saves it. Done before or after the payment
+   * is saved. Used by OffsiteOrderDataTest.
+   */
+  public function onReturn(OrderInterface $order, Request $request) {
+    $order->setData('test_offsite', ['test' => TRUE]);
+    $state = \Drupal::state();
+
+    if ($state->get('offsite_order_data_test_save') === 'before') {
+      $order->save();
+    }
+
+    parent::onReturn($order, $request);
+
+    if ($state->get('offsite_order_data_test_save') === 'after') {
+      $order->save();
+    }
+  }
+
+}
diff --git a/modules/payment/tests/src/FunctionalJavascript/OffsiteOrderDataTest.php b/modules/payment/tests/src/FunctionalJavascript/OffsiteOrderDataTest.php
new file mode 100644
index 00000000..7b75d4bc
--- /dev/null
+++ b/modules/payment/tests/src/FunctionalJavascript/OffsiteOrderDataTest.php
@@ -0,0 +1,128 @@
+<?php
+
+namespace Drupal\Tests\commerce_payment\FunctionalJavascript;
+
+use Drupal\commerce_order\Entity\Order;
+use Drupal\commerce_payment\Entity\PaymentGateway;
+use Drupal\Tests\commerce\FunctionalJavascript\CommerceWebDriverTestBase;
+
+/**
+ * Tests saving order data before and after saving the payment.
+ *
+ * @link https://www.drupal.org/project/commerce/issues/3011667
+ *
+ * @group commerce
+ */
+class OffsiteOrderDataTest extends CommerceWebDriverTestBase {
+
+  /**
+   * The product.
+   *
+   * @var \Drupal\commerce_product\Entity\ProductInterface
+   */
+  protected $product;
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = [
+    'commerce_product',
+    'commerce_cart',
+    'commerce_checkout',
+    'commerce_payment',
+    'commerce_payment_example',
+    'commerce_payment_test',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $variation = $this->createEntity('commerce_product_variation', [
+      'type' => 'default',
+      'sku' => strtolower($this->randomMachineName()),
+      'price' => [
+        'number' => '39.99',
+        'currency_code' => 'USD',
+      ],
+    ]);
+
+    /** @var \Drupal\commerce_product\Entity\ProductInterface $product */
+    $this->product = $this->createEntity('commerce_product', [
+      'type' => 'default',
+      'title' => 'My product',
+      'variations' => [$variation],
+      'stores' => [$this->store],
+    ]);
+
+    /** @var \Drupal\commerce_payment\Entity\PaymentGateway $gateway */
+    $gateway = PaymentGateway::create([
+      'id' => 'offsite',
+      'label' => 'Off-site',
+      'plugin' => 'test_offsite',
+      'configuration' => [
+        // PayPal uses GET, follow its pattern for this test.
+        'redirect_method' => 'get',
+        'payment_method_types' => ['credit_card'],
+      ],
+    ]);
+    $gateway->save();
+  }
+
+  /**
+   * Tests the order data saving.
+   *
+   * @dataProvider saveDataProvider
+   */
+  public function testSave($when_to_save) {
+    $state = $this->container->get('state');
+    $state->set('offsite_order_data_test_save', $when_to_save);
+
+    $this->drupalGet($this->product->toUrl()->toString());
+    $this->submitForm([], 'Add to cart');
+    $this->drupalGet('checkout/1');
+
+    $this->submitForm([
+      'payment_information[billing_information][address][0][address][given_name]' => 'Johnny',
+      'payment_information[billing_information][address][0][address][family_name]' => 'Appleseed',
+      'payment_information[billing_information][address][0][address][address_line1]' => '123 New York Drive',
+      'payment_information[billing_information][address][0][address][locality]' => 'New York City',
+      'payment_information[billing_information][address][0][address][administrative_area]' => 'NY',
+      'payment_information[billing_information][address][0][address][postal_code]' => '10001',
+    ], 'Continue to review');
+    $this->assertSession()->pageTextContains('Payment information');
+    $this->assertSession()->pageTextContains('Example');
+    $this->assertSession()->pageTextContains('Johnny Appleseed');
+    $this->assertSession()->pageTextContains('123 New York Drive');
+    $this->submitForm([], 'Pay and complete purchase');
+    $this->assertSession()->pageTextContains('Your order number is 1. You can view your order on your account page when logged in.');
+
+    $order = Order::load(1);
+    $this->assertEquals('offsite', $order->get('payment_gateway')->target_id);
+    $this->assertFalse($order->isLocked());
+    $this->assertTrue($order->isPaid());
+    $this->assertTrue($order->getData('paid_event_dispatched'));
+    // Confirm that gateway data was set and preserved.
+    $this->assertEquals($order->getData('test_offsite'), [
+      'test' => TRUE,
+    ]);
+  }
+
+  /**
+   * Data provider for ::testSave.
+   *
+   * @return array
+   *   A list of testSave function arguments.
+   */
+  public function saveDataProvider() {
+    return [
+      ['before'],
+      ['after'],
+    ];
+  }
+
+}
diff --git a/modules/payment/tests/src/FunctionalJavascript/PaymentCheckoutTest.php b/modules/payment/tests/src/FunctionalJavascript/PaymentCheckoutTest.php
index ec80a57b..8388da80 100644
--- a/modules/payment/tests/src/FunctionalJavascript/PaymentCheckoutTest.php
+++ b/modules/payment/tests/src/FunctionalJavascript/PaymentCheckoutTest.php
@@ -83,7 +83,7 @@ class PaymentCheckoutTest extends CommerceWebDriverTestBase {
       'stores' => [$this->store],
     ]);
 
-    /** @var \Drupal\commerce_payment\Entity\PaymentGateway $gateway */
+    /** @var \Drupal\commerce_payment\Entity\PaymentGateway $skipped_gateway */
     $skipped_gateway = PaymentGateway::create([
       'id' => 'onsite_skipped',
       'label' => 'On-site Skipped',
diff --git a/modules/payment/tests/src/Kernel/Entity/PaymentTest.php b/modules/payment/tests/src/Kernel/Entity/PaymentTest.php
index 12296486..e386143b 100644
--- a/modules/payment/tests/src/Kernel/Entity/PaymentTest.php
+++ b/modules/payment/tests/src/Kernel/Entity/PaymentTest.php
@@ -10,6 +10,7 @@ use Drupal\commerce_payment\Entity\Payment;
 use Drupal\commerce_payment\Plugin\Commerce\PaymentType\PaymentDefault;
 use Drupal\commerce_price\Price;
 use Drupal\Tests\commerce\Kernel\CommerceKernelTestBase;
+use Symfony\Component\HttpFoundation\Response;
 
 /**
  * Tests the payment entity.
@@ -197,18 +198,23 @@ class PaymentTest extends CommerceKernelTestBase {
       'state' => 'completed',
     ]);
     $payment->save();
-    $this->order = $this->reloadEntity($this->order);
+    $this->order->save();
     $this->assertEquals(new Price('30', 'USD'), $this->order->getTotalPaid());
     $this->assertEquals(new Price('0', 'USD'), $this->order->getBalance());
 
     $payment->setRefundedAmount(new Price('15', 'USD'));
     $payment->setState('partially_refunded');
     $payment->save();
-    $this->order = $this->reloadEntity($this->order);
+    $this->order->save();
     $this->assertEquals(new Price('15', 'USD'), $this->order->getTotalPaid());
     $this->assertEquals(new Price('15', 'USD'), $this->order->getBalance());
 
     $payment->delete();
+    // Confirm that if the order isn't explicitly saved, it will be saved
+    // at the end of the request.
+    $request = $this->container->get('request_stack')->getCurrentRequest();
+    $kernel = $this->container->get('kernel');
+    $kernel->terminate($request, new Response());
     $this->order = $this->reloadEntity($this->order);
     $this->assertEquals(new Price('0', 'USD'), $this->order->getTotalPaid());
     $this->assertEquals(new Price('30', 'USD'), $this->order->getBalance());
diff --git a/modules/payment/tests/src/Kernel/OrderPaidSubscriberTest.php b/modules/payment/tests/src/Kernel/OrderPaidSubscriberTest.php
index b1d320af..d4114656 100644
--- a/modules/payment/tests/src/Kernel/OrderPaidSubscriberTest.php
+++ b/modules/payment/tests/src/Kernel/OrderPaidSubscriberTest.php
@@ -105,8 +105,8 @@ class OrderPaidSubscriberTest extends CommerceKernelTestBase {
       'state' => 'completed',
     ]);
     $payment->save();
+    $this->order->save();
 
-    $this->order = $this->reloadEntity($this->order);
     $this->assertEquals('draft', $this->order->getState()->getId());
     $this->assertEmpty($this->order->getOrderNumber());
     $this->assertEmpty($this->order->getPlacedTime());
@@ -140,8 +140,8 @@ class OrderPaidSubscriberTest extends CommerceKernelTestBase {
       'state' => 'completed',
     ]);
     $payment->save();
+    $this->order->save();
 
-    $this->order = $this->reloadEntity($this->order);
     $this->assertEquals('completed', $this->order->getState()->getId());
     $this->assertFalse($this->order->isLocked());
     $this->assertNotEmpty($this->order->getOrderNumber());
diff --git a/modules/payment/tests/src/Kernel/PaymentOrderUpdaterTest.php b/modules/payment/tests/src/Kernel/PaymentOrderUpdaterTest.php
new file mode 100644
index 00000000..389f1e94
--- /dev/null
+++ b/modules/payment/tests/src/Kernel/PaymentOrderUpdaterTest.php
@@ -0,0 +1,205 @@
+<?php
+
+namespace Drupal\Tests\commerce_payment\Kernel;
+
+use Drupal\commerce_order\Entity\Order;
+use Drupal\commerce_order\Entity\OrderItem;
+use Drupal\commerce_order\Entity\OrderItemType;
+use Drupal\commerce_payment\Entity\Payment;
+use Drupal\commerce_payment\Entity\PaymentGateway;
+use Drupal\commerce_payment\Entity\PaymentMethod;
+use Drupal\commerce_price\Price;
+use Drupal\profile\Entity\Profile;
+use Drupal\Tests\commerce\Kernel\CommerceKernelTestBase;
+
+/**
+ * Tests the payment order updater.
+ *
+ * @coversDefaultClass \Drupal\commerce_payment\PaymentOrderUpdater
+ *
+ * @group commerce
+ */
+class PaymentOrderUpdaterTest extends CommerceKernelTestBase {
+
+  /**
+   * The payment order updater.
+   *
+   * @var \Drupal\commerce_payment\PaymentOrderUpdaterInterface
+   */
+  protected $paymentOrderUpdater;
+
+  /**
+   * A test user.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $user;
+
+  /**
+   * The first order.
+   *
+   * @var \Drupal\commerce_order\Entity\OrderInterface
+   */
+  protected $firstOrder;
+
+  /**
+   * The second order.
+   *
+   * @var \Drupal\commerce_order\Entity\OrderInterface
+   */
+  protected $secondOrder;
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = [
+    'address',
+    'entity_reference_revisions',
+    'profile',
+    'state_machine',
+    'commerce_product',
+    'commerce_order',
+    'commerce_payment',
+    'commerce_payment_example',
+    'commerce_payment_test',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->installEntitySchema('profile');
+    $this->installEntitySchema('commerce_order');
+    $this->installEntitySchema('commerce_order_item');
+    $this->installEntitySchema('commerce_payment');
+    $this->installEntitySchema('commerce_payment_method');
+    $this->installConfig('commerce_order');
+    $this->installConfig('commerce_payment');
+
+    $this->paymentOrderUpdater = $this->container->get('commerce_payment.order_updater');
+    $this->user = $this->createUser();
+
+    // An order item type that doesn't need a purchasable entity, for simplicity.
+    OrderItemType::create([
+      'id' => 'test',
+      'label' => 'Test',
+      'orderType' => 'default',
+    ])->save();
+
+    $payment_gateway = PaymentGateway::create([
+      'id' => 'onsite',
+      'label' => 'On-site',
+      'plugin' => 'example_onsite',
+    ]);
+    $payment_gateway->save();
+
+    $profile = Profile::create([
+      'type' => 'customer',
+      'address' => [
+        'country_code' => 'US',
+        'postal_code' => '53177',
+        'locality' => 'Milwaukee',
+        'address_line1' => 'Pabst Blue Ribbon Dr',
+        'administrative_area' => 'WI',
+        'given_name' => 'Frederick',
+        'family_name' => 'Pabst',
+      ],
+      'uid' => $this->user->id(),
+    ]);
+    $profile->save();
+
+    $payment_method = PaymentMethod::create([
+      'uid' => $this->user->id(),
+      'type' => 'credit_card',
+      'payment_gateway' => 'onsite',
+      'card_type' => 'visa',
+      'card_number' => '1111',
+      'billing_profile' => $profile,
+      'reusable' => TRUE,
+      'expires' => strtotime('2028/03/24'),
+    ]);
+    $payment_method->setBillingProfile($profile);
+    $payment_method->save();
+
+    $first_order_item = OrderItem::create([
+      'type' => 'test',
+      'quantity' => 1,
+      'unit_price' => new Price('10', 'USD'),
+    ]);
+    $first_order_item->save();
+
+    $first_order = Order::create([
+      'uid' => $this->user,
+      'type' => 'default',
+      'state' => 'draft',
+      'order_items' => [$first_order_item],
+      'store_id' => $this->store,
+    ]);
+    $first_order->save();
+    $this->firstOrder = $this->reloadEntity($first_order);
+
+    $second_order_item = OrderItem::create([
+      'type' => 'test',
+      'quantity' => 1,
+      'unit_price' => new Price('20', 'USD'),
+    ]);
+    $second_order_item->save();
+
+    $second_order = Order::create([
+      'uid' => $this->user,
+      'type' => 'default',
+      'state' => 'draft',
+      'order_items' => [$second_order_item],
+      'store_id' => $this->store,
+    ]);
+    $second_order->save();
+    $this->secondOrder = $this->reloadEntity($second_order);
+  }
+
+  /**
+   * @covers ::requestUpdate
+   * @covers ::needsUpdate
+   * @covers ::updateOrders
+   * @covers ::updateOrder
+   */
+  public function testUpdate() {
+    $this->assertTrue($this->firstOrder->getTotalPaid()->isZero());
+    $this->assertTrue($this->secondOrder->getTotalPaid()->isZero());
+
+    $this->assertFalse($this->paymentOrderUpdater->needsUpdate($this->firstOrder));
+    $this->assertFalse($this->paymentOrderUpdater->needsUpdate($this->secondOrder));
+    $this->paymentOrderUpdater->requestUpdate($this->firstOrder);
+    $this->assertTrue($this->paymentOrderUpdater->needsUpdate($this->firstOrder));
+    $this->assertFalse($this->paymentOrderUpdater->needsUpdate($this->secondOrder));
+
+    /** @var \Drupal\commerce_payment\Entity\PaymentInterface $payment */
+    $payment = Payment::create([
+      'type' => 'payment_default',
+      'payment_gateway' => 'onsite',
+      'order_id' => $this->firstOrder->id(),
+      'amount' => new Price('10', 'USD'),
+      'state' => 'completed',
+    ]);
+    $payment->save();
+
+    $this->paymentOrderUpdater->updateOrders();
+    $this->firstOrder = $this->reloadEntity($this->firstOrder);
+    $this->secondOrder = $this->reloadEntity($this->secondOrder);
+
+    $this->assertEquals($payment->getAmount(), $this->firstOrder->getTotalPaid());
+    $this->assertTrue($this->secondOrder->getTotalPaid()->isZero());
+
+    // Confirm that the order is not resaved if total_paid hasn't changed.
+    $changed = $this->firstOrder->getChangedTime();
+    sleep(1);
+    $this->paymentOrderUpdater->requestUpdate($this->firstOrder);
+    $this->paymentOrderUpdater->updateOrders();
+    $this->firstOrder = $this->reloadEntity($this->firstOrder);
+    $this->assertEquals($changed, $this->firstOrder->getChangedTime());
+  }
+
+}
diff --git a/modules/payment_example/src/Plugin/Commerce/PaymentGateway/OffsiteRedirect.php b/modules/payment_example/src/Plugin/Commerce/PaymentGateway/OffsiteRedirect.php
index 8cedb543..f699273c 100644
--- a/modules/payment_example/src/Plugin/Commerce/PaymentGateway/OffsiteRedirect.php
+++ b/modules/payment_example/src/Plugin/Commerce/PaymentGateway/OffsiteRedirect.php
@@ -74,7 +74,7 @@ class OffsiteRedirect extends OffsitePaymentGatewayBase {
     // @todo Add examples of request validation.
     $payment_storage = $this->entityTypeManager->getStorage('commerce_payment');
     $payment = $payment_storage->create([
-      'state' => 'authorization',
+      'state' => 'completed',
       'amount' => $order->getBalance(),
       'payment_gateway' => $this->entityId,
       'order_id' => $order->id(),