diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index a033d1da575..5da67fb07ae 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -445,22 +445,22 @@ function theme_settings_convert_to_config(array $theme_settings, Config $config)
     if ($key == 'default_logo') {
       $config->set('logo.use_default', $value);
     }
-    else if ($key == 'logo_path') {
+    elseif ($key == 'logo_path') {
       $config->set('logo.path', $value);
     }
-    else if ($key == 'default_favicon') {
+    elseif ($key == 'default_favicon') {
       $config->set('favicon.use_default', $value);
     }
-    else if ($key == 'favicon_path') {
+    elseif ($key == 'favicon_path') {
       $config->set('favicon.path', $value);
     }
-    else if ($key == 'favicon_mimetype') {
+    elseif ($key == 'favicon_mimetype') {
       $config->set('favicon.mimetype', $value);
     }
-    else if (substr($key, 0, 7) == 'toggle_') {
+    elseif (substr($key, 0, 7) == 'toggle_') {
       $config->set('features.' . Unicode::substr($key, 7), $value);
     }
-    else if (!in_array($key, array('theme', 'logo_upload'))) {
+    elseif (!in_array($key, array('theme', 'logo_upload'))) {
       $config->set($key, $value);
     }
   }
diff --git a/core/lib/Drupal/Core/Config/ConfigBase.php b/core/lib/Drupal/Core/Config/ConfigBase.php
index 0d66c66bd99..8263e9a6228 100644
--- a/core/lib/Drupal/Core/Config/ConfigBase.php
+++ b/core/lib/Drupal/Core/Config/ConfigBase.php
@@ -290,7 +290,7 @@ abstract class ConfigBase implements RefinableCacheableDependencyInterface {
     if ($data instanceof MarkupInterface) {
       $data = (string) $data;
     }
-    else if (is_array($data)) {
+    elseif (is_array($data)) {
       array_walk_recursive($data, function (&$value) {
         if ($value instanceof MarkupInterface) {
           $value = (string) $value;
diff --git a/core/lib/Drupal/Core/Datetime/Plugin/Field/FieldWidget/TimestampDatetimeWidget.php b/core/lib/Drupal/Core/Datetime/Plugin/Field/FieldWidget/TimestampDatetimeWidget.php
index 66ac11d84ee..fd64c57a059 100644
--- a/core/lib/Drupal/Core/Datetime/Plugin/Field/FieldWidget/TimestampDatetimeWidget.php
+++ b/core/lib/Drupal/Core/Datetime/Plugin/Field/FieldWidget/TimestampDatetimeWidget.php
@@ -54,7 +54,7 @@ class TimestampDatetimeWidget extends WidgetBase {
       if (isset($item['value']) && $item['value'] instanceof DrupalDateTime) {
         $date = $item['value'];
       }
-      else if (isset($item['value']['object']) && $item['value']['object'] instanceof DrupalDateTime) {
+      elseif (isset($item['value']['object']) && $item['value']['object'] instanceof DrupalDateTime) {
         $date = $item['value']['object'];
       }
       else {
diff --git a/core/lib/Drupal/Core/DependencyInjection/Compiler/TaggedHandlersPass.php b/core/lib/Drupal/Core/DependencyInjection/Compiler/TaggedHandlersPass.php
index aad1dcd694f..16eb59a0bb3 100644
--- a/core/lib/Drupal/Core/DependencyInjection/Compiler/TaggedHandlersPass.php
+++ b/core/lib/Drupal/Core/DependencyInjection/Compiler/TaggedHandlersPass.php
@@ -99,10 +99,10 @@ class TaggedHandlersPass implements CompilerPassInterface {
           if ($param->getClass()) {
             $interface = $param->getClass();
           }
-          else if ($param->getName() === 'id') {
+          elseif ($param->getName() === 'id') {
             $id_pos = $pos;
           }
-          else if ($param->getName() === 'priority') {
+          elseif ($param->getName() === 'priority') {
             $priority_pos = $pos;
           }
           else {
diff --git a/core/lib/Drupal/Core/StreamWrapper/StreamWrapperManager.php b/core/lib/Drupal/Core/StreamWrapper/StreamWrapperManager.php
index 6886bb20f48..a28fc5147ac 100644
--- a/core/lib/Drupal/Core/StreamWrapper/StreamWrapperManager.php
+++ b/core/lib/Drupal/Core/StreamWrapper/StreamWrapperManager.php
@@ -52,7 +52,7 @@ class StreamWrapperManager extends ContainerAware implements StreamWrapperManage
     if (isset($this->wrappers[$filter])) {
       return $this->wrappers[$filter];
     }
-    else if (isset($this->wrappers[StreamWrapperInterface::ALL])) {
+    elseif (isset($this->wrappers[StreamWrapperInterface::ALL])) {
       $this->wrappers[$filter] = array();
       foreach ($this->wrappers[StreamWrapperInterface::ALL] as $scheme => $info) {
         // Bit-wise filter.
diff --git a/core/lib/Drupal/Core/Template/TwigNodeVisitor.php b/core/lib/Drupal/Core/Template/TwigNodeVisitor.php
index 860cc5628ee..05468c1ad2b 100644
--- a/core/lib/Drupal/Core/Template/TwigNodeVisitor.php
+++ b/core/lib/Drupal/Core/Template/TwigNodeVisitor.php
@@ -45,7 +45,7 @@ class TwigNodeVisitor extends \Twig_BaseNodeVisitor {
       );
     }
     // Change the 'escape' filter to our own 'drupal_escape' filter.
-    else if ($node instanceof \Twig_Node_Expression_Filter) {
+    elseif ($node instanceof \Twig_Node_Expression_Filter) {
       $name = $node->getNode('filter')->getAttribute('value');
       if ('escape' == $name || 'e' == $name) {
         // Use our own escape filter that is SafeMarkup aware.
diff --git a/core/modules/filter/src/Entity/FilterFormat.php b/core/modules/filter/src/Entity/FilterFormat.php
index 7419a15d04f..dae2cfd3b28 100644
--- a/core/modules/filter/src/Entity/FilterFormat.php
+++ b/core/modules/filter/src/Entity/FilterFormat.php
@@ -338,19 +338,19 @@ class FilterFormat extends ConfigEntityBase implements FilterFormatInterface, En
                   continue;
                 }
                 // The new filter allows less attributes (all -> list or none).
-                else if (!is_array($current_attributes) && $current_attributes == TRUE && ($new_attributes == FALSE || is_array($new_attributes))) {
+                elseif (!is_array($current_attributes) && $current_attributes == TRUE && ($new_attributes == FALSE || is_array($new_attributes))) {
                   $intersection[$tag] = $new_attributes;
                 }
                 // The new filter allows less attributes (list -> none).
-                else if (is_array($current_attributes) && $new_attributes == FALSE) {
+                elseif (is_array($current_attributes) && $new_attributes == FALSE) {
                   $intersection[$tag] = $new_attributes;
                 }
                 // The new filter allows more attributes; retain current.
-                else if (is_array($current_attributes) && $new_attributes == TRUE) {
+                elseif (is_array($current_attributes) && $new_attributes == TRUE) {
                   continue;
                 }
                 // The new filter allows the same attributes; retain current.
-                else if ($current_attributes == $new_attributes) {
+                elseif ($current_attributes == $new_attributes) {
                   continue;
                 }
                 // Both list an array of attribute values; do an intersection,
diff --git a/core/modules/shortcut/shortcut.module b/core/modules/shortcut/shortcut.module
index f6667e0ee0d..066afcc953b 100644
--- a/core/modules/shortcut/shortcut.module
+++ b/core/modules/shortcut/shortcut.module
@@ -102,7 +102,7 @@ function shortcut_set_switch_access($account = NULL) {
   if (!isset($account)) {
     return AccessResult::allowed()->cachePerPermissions();
   }
-  else if ($user->id() == $account->id()) {
+  elseif ($user->id() == $account->id()) {
     return AccessResult::allowed()->cachePerPermissions()->cachePerUser();
   }
 
diff --git a/core/modules/simpletest/src/WebTestBase.php b/core/modules/simpletest/src/WebTestBase.php
index 2edfc819781..1e3bfdb0865 100644
--- a/core/modules/simpletest/src/WebTestBase.php
+++ b/core/modules/simpletest/src/WebTestBase.php
@@ -2970,7 +2970,7 @@ abstract class WebTestBase extends TestBase {
     }
     // The URL generator service is not necessarily available yet; e.g., in
     // interactive installer tests.
-    else if ($this->container->has('url_generator')) {
+    elseif ($this->container->has('url_generator')) {
       $force_internal = isset($options['external']) && $options['external'] == FALSE;
       if (!$force_internal && UrlHelper::isExternal($path)) {
         return Url::fromUri($path, $options)->toString();
diff --git a/core/modules/system/src/Tests/Theme/TwigTransTest.php b/core/modules/system/src/Tests/Theme/TwigTransTest.php
index 6bfe4421b30..867c4d5bae2 100644
--- a/core/modules/system/src/Tests/Theme/TwigTransTest.php
+++ b/core/modules/system/src/Tests/Theme/TwigTransTest.php
@@ -256,7 +256,7 @@ msgid "I have context."
 msgstr "I HAZ KONTEX."
 EOF;
     }
-    else if ($langcode === 'zz') {
+    elseif ($langcode === 'zz') {
       return <<< EOF
 msgid ""
 msgstr ""
diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index fa7658beb8e..afa58923ce6 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -99,18 +99,18 @@ function system_requirements($phase) {
       if ($matches[1] < 2) {
         $rewrite_error = TRUE;
       }
-      else if ($matches[1] == 2) {
+      elseif ($matches[1] == 2) {
         if (!isset($matches[2])) {
           $rewrite_warning = TRUE;
         }
-        else if ($matches[2] < 2) {
+        elseif ($matches[2] < 2) {
           $rewrite_error = TRUE;
         }
-        else if ($matches[2] == 2) {
+        elseif ($matches[2] == 2) {
           if (!isset($matches[3])) {
             $rewrite_warning = TRUE;
           }
-          else if ($matches[3] < 16) {
+          elseif ($matches[3] < 16) {
             $rewrite_error = TRUE;
           }
         }
diff --git a/core/modules/tour/src/Tests/TourTestBase.php b/core/modules/tour/src/Tests/TourTestBase.php
index c6372cde9a1..06a7a08e2bf 100644
--- a/core/modules/tour/src/Tests/TourTestBase.php
+++ b/core/modules/tour/src/Tests/TourTestBase.php
@@ -58,7 +58,7 @@ abstract class TourTestBase extends WebTestBase {
           $elements = \PHPUnit_Util_XML::cssSelect('#' . $tip['data-id'], TRUE, $this->content, TRUE);
           $this->assertTrue(!empty($elements) && count($elements) === 1, format_string('Found corresponding page element for tour tip with id #%data-id', array('%data-id' => $tip['data-id'])));
         }
-        else if (!empty($tip['data-class'])) {
+        elseif (!empty($tip['data-class'])) {
           $elements = \PHPUnit_Util_XML::cssSelect('.' . $tip['data-class'], TRUE, $this->content, TRUE);
           $this->assertFalse(empty($elements), format_string('Found corresponding page element for tour tip with class .%data-class', array('%data-class' => $tip['data-class'])));
         }
diff --git a/core/modules/user/src/UserAccessControlHandler.php b/core/modules/user/src/UserAccessControlHandler.php
index 605f7c7d161..ae52b2bc5a8 100644
--- a/core/modules/user/src/UserAccessControlHandler.php
+++ b/core/modules/user/src/UserAccessControlHandler.php
@@ -44,7 +44,7 @@ class UserAccessControlHandler extends EntityAccessControlHandler {
           return AccessResult::allowed()->cachePerPermissions()->cacheUntilEntityChanges($entity);
         }
         // Users can view own profiles at all times.
-        else if ($account->id() == $entity->id()) {
+        elseif ($account->id() == $entity->id()) {
           return AccessResult::allowed()->cachePerUser();
         }
         break;
diff --git a/core/modules/views/src/Plugin/views/PluginBase.php b/core/modules/views/src/Plugin/views/PluginBase.php
index b58037ef3db..462d53f7ff6 100644
--- a/core/modules/views/src/Plugin/views/PluginBase.php
+++ b/core/modules/views/src/Plugin/views/PluginBase.php
@@ -250,7 +250,7 @@ abstract class PluginBase extends ComponentPluginBase implements ContainerFactor
 
         $this->unpackOptions($storage[$key], $value, isset($definition[$key]['contains']) ? $definition[$key]['contains'] : array(), $all, FALSE);
       }
-      else if ($all || !empty($definition[$key])) {
+      elseif ($all || !empty($definition[$key])) {
         $storage[$key] = $value;
       }
     }
diff --git a/core/modules/views/src/Plugin/views/filter/InOperator.php b/core/modules/views/src/Plugin/views/filter/InOperator.php
index 5d0ae74a853..3e3482a0262 100644
--- a/core/modules/views/src/Plugin/views/filter/InOperator.php
+++ b/core/modules/views/src/Plugin/views/filter/InOperator.php
@@ -349,7 +349,7 @@ class InOperator extends FilterPluginBase {
       if (count($this->value) == 0) {
         $values = $this->t('Unknown');
       }
-      else if (count($this->value) == 1) {
+      elseif (count($this->value) == 1) {
         // If any, use the 'single' short name of the operator instead.
         if (isset($info[$this->operator]['short_single'])) {
           $operator = $info[$this->operator]['short_single'];
diff --git a/core/phpcs.xml.dist b/core/phpcs.xml.dist
index 4015e140719..4d5c950bdc2 100644
--- a/core/phpcs.xml.dist
+++ b/core/phpcs.xml.dist
@@ -25,7 +25,6 @@
     <exclude name="Drupal.Commenting.InlineComment"/>
     <exclude name="Drupal.Commenting.PostStatementComment"/>
     <exclude name="Drupal.ControlStructures.ControlSignature"/>
-    <exclude name="Drupal.ControlStructures.ElseIf"/>
     <exclude name="Drupal.ControlStructures.InlineControlStructure"/>
     <exclude name="Drupal.Files.EndFileNewline"/>
     <exclude name="Drupal.Files.LineLength"/>
diff --git a/core/scripts/generate-d7-content.sh b/core/scripts/generate-d7-content.sh
index 9925fe1bb9d..8b591f42b03 100644
--- a/core/scripts/generate-d7-content.sh
+++ b/core/scripts/generate-d7-content.sh
@@ -168,10 +168,10 @@ for ($i = 0; $i < 36; $i++) {
   if ($i < 12) {
     $node->type = 'page';
   }
-  else if ($i < 24) {
+  elseif ($i < 24) {
     $node->type = 'story';
   }
-  else if (module_exists('blog')) {
+  elseif (module_exists('blog')) {
     $node->type = 'blog';
   }
   $node->sticky = 0;
diff --git a/core/tests/Drupal/Tests/Core/Access/AccessResultTest.php b/core/tests/Drupal/Tests/Core/Access/AccessResultTest.php
index 2c46a0b1df1..287c344d5ce 100644
--- a/core/tests/Drupal/Tests/Core/Access/AccessResultTest.php
+++ b/core/tests/Drupal/Tests/Core/Access/AccessResultTest.php
@@ -798,7 +798,7 @@ class AccessResultTest extends UnitTestCase {
     if ($op === 'OR') {
       $result = $first->orIf($second);
     }
-    else if ($op === 'AND') {
+    elseif ($op === 'AND') {
       $result = $first->andIf($second);
     }
     else {