diff --git a/src/ConfigListerWithProviders.php b/src/ConfigListerWithProviders.php
index 5c50c98..cc0f635 100644
--- a/src/ConfigListerWithProviders.php
+++ b/src/ConfigListerWithProviders.php
@@ -85,11 +85,12 @@ class ConfigListerWithProviders extends ConfigLister implements ConfigListByProv
       return $this->providers;
     }
 
-    // Calculate if it hasn't been set up yet.
-    // List all of the profile, modules, and themes.
+    // Calculate the list of who provides which config, if it hasn't been set
+    // up yet. List all of the profile, modules, and themes. Profile needs to
+    // come last, so it will override config in modules and themes in our list,
+    // matching what the config system does.
     $extensionsToDo = [];
     $profile = $this->getProfileName();
-    $extensionsToDo[] = ['profile', $profile];
     $modules = $this->moduleHandler->getModuleList();
     foreach ($modules as $machine_name => $module) {
       if ($machine_name != $profile) {
@@ -102,6 +103,8 @@ class ConfigListerWithProviders extends ConfigLister implements ConfigListByProv
       $extensionsToDo[] = ['theme', $machine_name];
     }
 
+    $extensionsToDo[] = ['profile', $profile];
+
     // For each extension, figure out if it has config, and make an index of
     // config item => provider.
     $this->extensionsWithConfig = [
diff --git a/tests/src/Unit/ConfigListerTest.php b/tests/src/Unit/ConfigListerTest.php
index 668e8b9..d9d1952 100644
--- a/tests/src/Unit/ConfigListerTest.php
+++ b/tests/src/Unit/ConfigListerTest.php
@@ -24,15 +24,21 @@ class ConfigListerTest extends ConfigUpdateUnitTestBase {
    * List of configuration by provider in the mocks.
    *
    * This is an array whose keys are provider names, and whose values are
-   * each an array containing the provider type, the name of one config item
-   * mocked to be in config/install, and one in config/optional.
+   * each an array containing the provider type, an array of config items
+   * mocked to be in config/install, and the same for config/optional. In
+   * all cases, the first item in the array of config items should be tested
+   * to be provided by that provider, and any others should not be there.
    *
    * @var array
    */
   protected $configProviderList = [
-    'foo_module' => ['module', 'foo.barbaz.one', 'foo.barbaz.two'],
-    'foo_theme' => ['theme', 'foo.bar.one', 'foo.bar.two'],
-    'standard' => ['profile', 'baz.bar.one', 'baz.bar.two'],
+    'foo_module' => [
+      'module',
+      ['foo.barbaz.one', 'baz.bar.one'],
+      ['foo.barbaz.two'],
+    ],
+    'foo_theme' => ['theme', ['foo.bar.one'], ['foo.bar.two']],
+    'standard' => ['profile', ['baz.bar.one'], ['baz.bar.two']],
   ];
 
   /**
@@ -56,10 +62,10 @@ class ConfigListerTest extends ConfigUpdateUnitTestBase {
 
     $map = [];
     foreach ($this->configProviderList as $provider => $info) {
-      // Info has: [type, install storage item, optional storage item].
+      // Info has: [type, install storage items, optional storage items].
       // Map needs: [type, provider name, isOptional, [config items]].
-      $map[] = [$info[0], $provider, FALSE, [$info[1]]];
-      $map[] = [$info[0], $provider, TRUE, [$info[2]]];
+      $map[] = [$info[0], $provider, FALSE, $info[1]];
+      $map[] = [$info[0], $provider, TRUE, $info[2]];
     }
     $lister->method('listProvidedItems')
       ->will($this->returnValueMap($map));
@@ -148,7 +154,7 @@ class ConfigListerTest extends ConfigUpdateUnitTestBase {
             'something.else',
             'another.one',
           ],
-          ['foo.barbaz.one'],
+          ['foo.barbaz.one', 'baz.bar.one'],
           ['foo.barbaz.two'],
         ],
       ],
@@ -233,10 +239,12 @@ class ConfigListerTest extends ConfigUpdateUnitTestBase {
     $return = $this->configLister->listProviders();
     $expected = [];
     foreach ($this->configProviderList as $provider => $info) {
-      // Info has: [type, install storage item, optional storage item].
+      // Info has: [type, install storage items, optional storage items], with
+      // only the first item in each list that should be present in
+      // listProviders().
       // Expected needs: key is item name, value is [type, provider name].
-      $expected[$info[1]] = [$info[0], $provider];
-      $expected[$info[2]] = [$info[0], $provider];
+      $expected[$info[1][0]] = [$info[0], $provider];
+      $expected[$info[2][0]] = [$info[0], $provider];
     }
     ksort($return);
     ksort($expected);
@@ -257,10 +265,12 @@ class ConfigListerTest extends ConfigUpdateUnitTestBase {
   public function getConfigProviderProvider() {
     $values = [];
     foreach ($this->configProviderList as $provider => $info) {
-      // Info has: [type, install storage item, optional storage item].
+      // Info has: [type, install storage items, optional storage items], with
+      // the first item in each list that should be OK to test with
+      // getConfigProvider().
       // Values needs: [item, [type, provider name]].
-      $values[] = [$info[1], [$info[0], $provider]];
-      $values[] = [$info[2], [$info[0], $provider]];
+      $values[] = [$info[1][0], [$info[0], $provider]];
+      $values[] = [$info[2][0], [$info[0], $provider]];
     }
     $values[] = ['not.a.config.item', NULL];
     return $values;
@@ -280,7 +290,7 @@ class ConfigListerTest extends ConfigUpdateUnitTestBase {
   public function providerHasConfigProvider() {
     $values = [];
     foreach ($this->configProviderList as $provider => $info) {
-      // Info has: [type, install storage item, optional storage item].
+      // Info has: [type, install storage items, optional storage items].
       // Values needs: [type, provider name, TRUE] for valid providers,
       // change the last to FALSE for invalid providers.
       $values[] = [$info[0], $provider, TRUE];