diff --git a/core/modules/user/lib/Drupal/user/AccountFormController.php b/core/modules/user/lib/Drupal/user/AccountFormController.php
index 138b86e..0672b1e 100644
--- a/core/modules/user/lib/Drupal/user/AccountFormController.php
+++ b/core/modules/user/lib/Drupal/user/AccountFormController.php
@@ -258,13 +258,12 @@ public function validate(array $form, array &$form_state) {
       // Cast the user ID as an integer. It might have been set to NULL, which
       // could lead to unexpected results.
       else {
-        $name_taken = (bool) db_select('users')
-        ->fields('users', array('uid'))
-        ->condition('uid', (int) $account->id(), '<>')
-        ->condition('name', db_like($form_state['values']['name']), 'LIKE')
-        ->range(0, 1)
-        ->execute()
-        ->fetchField();
+        $name_taken = (bool) \Drupal::entityQuery('user')
+          ->condition('uid', (int) $account->id(), '<>')
+          ->condition('name', db_like($form_state['values']['name']), 'LIKE')
+          ->range(0, 1)
+          ->count()
+          ->execute();
 
         if ($name_taken) {
           form_set_error('name', $this->t('The name %name is already taken.', array('%name' => $form_state['values']['name'])));
@@ -275,13 +274,12 @@ public function validate(array $form, array &$form_state) {
     $mail = $form_state['values']['mail'];
 
     if (!empty($mail)) {
-      $mail_taken = (bool) db_select('users')
-      ->fields('users', array('uid'))
-      ->condition('uid', (int) $account->id(), '<>')
-      ->condition('mail', db_like($mail), 'LIKE')
-      ->range(0, 1)
-      ->execute()
-      ->fetchField();
+      $mail_taken = (bool) \Drupal::entityQuery('user')
+        ->condition('uid', (int) $account->id(), '<>')
+        ->condition('mail', db_like($mail), 'LIKE')
+        ->range(0, 1)
+        ->count()
+        ->execute();
 
       if ($mail_taken) {
         // Format error message dependent on whether the user is logged in or not.
diff --git a/core/modules/user/lib/Drupal/user/Plugin/Block/UserNewBlock.php b/core/modules/user/lib/Drupal/user/Plugin/Block/UserNewBlock.php
index 71b28e3..8dbf988 100644
--- a/core/modules/user/lib/Drupal/user/Plugin/Block/UserNewBlock.php
+++ b/core/modules/user/lib/Drupal/user/Plugin/Block/UserNewBlock.php
@@ -65,7 +65,13 @@ public function blockSubmit($form, &$form_state) {
    */
   public function build() {
     // Retrieve a list of new users who have accessed the site successfully.
-    $uids = db_query_range('SELECT uid FROM {users} WHERE status <> 0 AND access <> 0 ORDER BY created DESC', 0, $this->configuration['whois_new_count'])->fetchCol();
+    $uids = \Drupal::entityQuery('user')
+      ->condition('status', 0, '<>')
+      ->condition('access', 0, '<>')
+      ->sort('created', 'DESC')
+      ->range(0, $this->configuration['whois_new_count'])
+      ->execute();
+
     $build = array(
       '#theme' => 'item_list__user__new',
       '#items' => array(),
diff --git a/core/modules/user/lib/Drupal/user/Plugin/Block/UserOnlineBlock.php b/core/modules/user/lib/Drupal/user/Plugin/Block/UserOnlineBlock.php
index 7370b7a..4256610 100644
--- a/core/modules/user/lib/Drupal/user/Plugin/Block/UserOnlineBlock.php
+++ b/core/modules/user/lib/Drupal/user/Plugin/Block/UserOnlineBlock.php
@@ -82,7 +82,10 @@ public function build() {
     $interval = REQUEST_TIME - $this->configuration['seconds_online'];
 
     // Perform database queries to gather online user lists.
-    $authenticated_count = db_query("SELECT COUNT(uid) FROM {users} WHERE access >= :timestamp", array(':timestamp' => $interval))->fetchField();
+    $authenticated_count = \Drupal::entityQuery('user')
+      ->condition('access', $interval, '>=')
+      ->count()
+      ->execute();
 
     $build = array(
       '#theme' => 'item_list__user__online',
@@ -92,7 +95,13 @@ public function build() {
     // Display a list of currently online users.
     $max_users = $this->configuration['max_list_count'];
     if ($authenticated_count && $max_users) {
-      $uids = db_query_range('SELECT uid FROM {users} WHERE access >= :interval AND uid > 0 ORDER BY access DESC', 0, $max_users, array(':interval' => $interval))->fetchCol();
+      $uids = \Drupal::entityQuery('user')
+        ->condition('access', $interval, '>=')
+        ->condition('uid', 0, '>')
+        ->sort('access', 'DESC')
+        ->range(0, $max_users)
+        ->execute();
+
       foreach (user_load_multiple($uids) as $account) {
         $username = array(
           '#theme' => 'username',
diff --git a/core/modules/user/lib/Drupal/user/Plugin/Validation/Constraint/UserUniqueValidator.php b/core/modules/user/lib/Drupal/user/Plugin/Validation/Constraint/UserUniqueValidator.php
index 945223f..6908685 100644
--- a/core/modules/user/lib/Drupal/user/Plugin/Validation/Constraint/UserUniqueValidator.php
+++ b/core/modules/user/lib/Drupal/user/Plugin/Validation/Constraint/UserUniqueValidator.php
@@ -22,14 +22,13 @@ public function validate($value, Constraint $constraint) {
     $field = $this->context->getMetadata()->getTypedData()->getParent();
     $uid = $field->getParent()->id();
 
-    $value_taken = (bool) db_select('users')
-      ->fields('users', array('uid'))
+    $value_taken = (bool) \Drupal::entityQuery('user')
       // The UID could be NULL, so we cast it to 0 in that case.
       ->condition('uid', (int) $uid, '<>')
       ->condition($field->getName(), db_like($value), 'LIKE')
       ->range(0, 1)
-      ->execute()
-      ->fetchField();
+      ->count()
+      ->execute();
 
     if ($value_taken) {
       $this->context->addViolation($constraint->message, array("%value" => $value));
diff --git a/core/modules/user/lib/Drupal/user/UserAutocomplete.php b/core/modules/user/lib/Drupal/user/UserAutocomplete.php
index 4d36923..c92710f 100644
--- a/core/modules/user/lib/Drupal/user/UserAutocomplete.php
+++ b/core/modules/user/lib/Drupal/user/UserAutocomplete.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Config\ConfigFactory;
 use Drupal\Core\Database\Connection;
+use Drupal\Component\Utility\String;
 
 /**
  * Defines a helper class to get user autocompletion results.
@@ -65,9 +66,15 @@ public function getMatches($string, $include_anonymous = FALSE) {
           $matches[$anonymous_name] = check_plain($anonymous_name);
         }
       }
-      $result = $this->connection->select('users')->fields('users', array('name'))->condition('name', db_like($string) . '%', 'LIKE')->range(0, 10)->execute();
-      foreach ($result as $account) {
-        $matches[$account->name] = check_plain($account->name);
+
+      $uids = \Drupal::entityQuery('user')
+        ->condition('name', $string, 'STARTS_WITH')
+        ->range(0, 10)
+        ->execute();
+
+      $controller = \Drupal::entityManager()->getStorageController('user');
+      foreach ($controller->loadMultiple($uids) as $account) {
+        $matches[$account->getUsername()] = String::checkPlain($account->getUsername());
       }
     }
 
diff --git a/core/modules/user/lib/Drupal/user/UserStorageController.php b/core/modules/user/lib/Drupal/user/UserStorageController.php
index 03d32b1..eb9681b 100644
--- a/core/modules/user/lib/Drupal/user/UserStorageController.php
+++ b/core/modules/user/lib/Drupal/user/UserStorageController.php
@@ -114,7 +114,7 @@ public function save(EntityInterface $entity) {
   /**
    * {@inheritdoc}
    */
-  public function saveRoles(EntityInterface $user) {
+  public function saveRoles(UserInterface $user) {
     $query = $this->database->insert('users_roles')->fields(array('uid', 'rid'));
     foreach ($user->getRoles() as $rid) {
       if (!in_array($rid, array(DRUPAL_ANONYMOUS_RID, DRUPAL_AUTHENTICATED_RID))) {
@@ -131,7 +131,7 @@ public function saveRoles(EntityInterface $user) {
    * {@inheritdoc}
    */
   public function addRoles(array $users) {
-    $result = db_query('SELECT rid, uid FROM {users_roles} WHERE uid IN (:uids)', array(':uids' => array_keys($users)));
+    $result = $this->database->query('SELECT rid, uid FROM {users_roles} WHERE uid IN (:uids)', array(':uids' => array_keys($users)));
     foreach ($result as $record) {
       $users[$record->uid]->roles[] = $record->rid;
     }
@@ -146,4 +146,14 @@ public function deleteUserRoles(array $uids) {
       ->execute();
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function updateLastLoginTimestamp(UserInterface $account) {
+    $this->database->update('users')
+      ->fields(array('login' => $account->getLastLoginTime()))
+      ->condition('uid', $account->id())
+      ->execute();
+  }
+
 }
diff --git a/core/modules/user/lib/Drupal/user/UserStorageControllerInterface.php b/core/modules/user/lib/Drupal/user/UserStorageControllerInterface.php
index 8768869..4797002 100644
--- a/core/modules/user/lib/Drupal/user/UserStorageControllerInterface.php
+++ b/core/modules/user/lib/Drupal/user/UserStorageControllerInterface.php
@@ -25,9 +25,9 @@ public function addRoles(array $users);
   /**
    * Save the user's roles.
    *
-   * @param \Drupal\Core\Entity\EntityInterface $user
+   * @param \Drupal\user\UserInterface $account
    */
-  public function saveRoles(EntityInterface $user);
+  public function saveRoles(UserInterface $user);
 
   /**
    * Remove the roles of a user.
@@ -36,4 +36,10 @@ public function saveRoles(EntityInterface $user);
    */
   public function deleteUserRoles(array $uids);
 
+  /**
+   * Update the last login timestamp of the user.
+   *
+   * @param \Drupal\user\UserInterface $account
+   */
+  public function updateLastLoginTimestamp(UserInterface $account);
 }
diff --git a/core/modules/user/user.admin.inc b/core/modules/user/user.admin.inc
index 4caec43..42bb22a 100644
--- a/core/modules/user/user.admin.inc
+++ b/core/modules/user/user.admin.inc
@@ -10,30 +10,19 @@
  */
 function user_admin_account() {
   $header = array(
-    'username' => array('data' => t('Username'), 'field' => 'u.name'),
-    'status' => array('data' => t('Status'), 'field' => 'u.status', 'class' => array(RESPONSIVE_PRIORITY_LOW)),
+    'username' => array('data' => t('Username'), 'specifier' => 'username'),
+    'status' => array('data' => t('Status'), 'specifier' => 'status', 'class' => array(RESPONSIVE_PRIORITY_LOW)),
     'roles' => array('data' => t('Roles'), 'class' => array(RESPONSIVE_PRIORITY_LOW)),
-    'member_for' => array('data' => t('Member for'), 'field' => 'u.created', 'sort' => 'desc', 'class' => array(RESPONSIVE_PRIORITY_LOW)),
-    'access' => array('data' => t('Last access'), 'field' => 'u.access', 'class' => array(RESPONSIVE_PRIORITY_LOW)),
+    'member_for' => array('data' => t('Member for'), 'specifier' => 'created', 'sort' => 'desc', 'class' => array(RESPONSIVE_PRIORITY_LOW)),
+    'access' => array('data' => t('Last access'), 'specifier' => 'access', 'class' => array(RESPONSIVE_PRIORITY_LOW)),
     'operations' => t('Operations'),
   );
 
-  $query = db_select('users', 'u');
-  $query->condition('u.uid', 0, '<>');
-
-  $count_query = clone $query;
-  $count_query->addExpression('COUNT(u.uid)');
-
-  $query = $query
-    ->extend('Drupal\Core\Database\Query\PagerSelectExtender')
-    ->extend('Drupal\Core\Database\Query\TableSortExtender');
-  $query
-    ->fields('u', array('uid'))
-    ->limit(50)
-    ->orderByHeader($header)
-    ->setCountQuery($count_query);
-  $uids = $query->execute()
-    ->fetchCol('uid');
+  $uids = Drupal::entityQuery('user')
+    ->condition('uid', 0, '<>')
+    ->tableSort($header)
+    ->pager(50)
+    ->execute();
 
   $destination = drupal_get_destination();
   $accounts = user_load_multiple($uids);
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index 24aee74..9e1259e 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -460,11 +460,10 @@ function user_access($string, AccountInterface $account = NULL) {
  *   FALSE if the user is not blocked.
  */
 function user_is_blocked($name) {
-  return db_select('users')
-    ->fields('users', array('name'))
+  return Drupal::entityQuery('user')
     ->condition('name', db_like($name), 'LIKE')
     ->condition('status', 0)
-    ->execute()->fetchObject();
+    ->execute();
 }
 
 /**
@@ -1048,21 +1047,20 @@ function user_authenticate($name, $password) {
 function user_login_finalize(UserInterface $account) {
   global $user;
   $user = $account;
-  watchdog('user', 'Session opened for %name.', array('%name' => $user->getUsername()));
+  watchdog('user', 'Session opened for %name.', array('%name' => $account->getUsername()));
   // Update the user table timestamp noting user has logged in.
   // This is also used to invalidate one-time login links.
   $account->setLastLoginTime(REQUEST_TIME);
-  db_update('users')
-    ->fields(array('login' => $user->getLastLoginTime()))
-    ->condition('uid', $user->id())
-    ->execute();
+  \Drupal::entityManager()
+    ->getStorageController('user')
+    ->updateLastLoginTimestamp($account);
 
   // Regenerate the session ID to prevent against session fixation attacks.
   // This is called before hook_user in case one of those functions fails
   // or incorrectly does a redirect which would leave the old session in place.
   drupal_session_regenerate();
 
-  \Drupal::moduleHandler()->invokeAll('user_login', array($user));
+  \Drupal::moduleHandler()->invokeAll('user_login', array($account));
 }
 
 /**
@@ -1834,12 +1832,12 @@ function user_node_load($nodes, $types) {
     $uids[$nid] = $node->getAuthorId();
   }
 
-  // Fetch name and data for these users.
-  $user_names = db_query("SELECT uid, name FROM {users} WHERE uid IN (:uids)", array(':uids' => $uids))->fetchAllKeyed();
-
-  // Add these values back into the node objects.
+  // Add loaded user name values back into the node objects.
+  $users = \Drupal::entityManager()
+    ->getStorageController('user')
+    ->loadMultiple($uids);
   foreach ($uids as $nid => $uid) {
-    $nodes[$nid]->name = $user_names[$uid];
+    $nodes[$nid]->name = $users[$uid]->getUsername();
   }
 }