diff --git a/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php b/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
index d0f7474577468bab32c63c7febfa28b0214b8a16..8ada1075b6a01ebb49490102389500cdfa5c6675 100644
--- a/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
+++ b/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
@@ -558,7 +558,7 @@ public static function submit($form, FormStateInterface $form_state) {
     }
 
     // If there are more files uploaded via the same widget, we have to separate
-    // them, as we display each file in it's own widget.
+    // them, as we display each file in its own widget.
     $new_values = array();
     foreach ($submitted_values as $delta => $submitted_value) {
       if (is_array($submitted_value['fids'])) {
diff --git a/core/modules/outside_in/css/outside_in.theme.css b/core/modules/outside_in/css/outside_in.theme.css
index 438fbb25eb3d4b0850edfa7a92b9175a6d18c147..d76a6eca7ca4e8683bb9560f6e346c7c29324ed2 100644
--- a/core/modules/outside_in/css/outside_in.theme.css
+++ b/core/modules/outside_in/css/outside_in.theme.css
@@ -199,7 +199,7 @@
 
 /**
  * Visual styling for buttons in the Settings Tray module's off canvas tray.
- * @todo Move to it's own component:
+ * @todo Move to its own component:
  *   https://www.drupal.org/node/1945262.
  */
 
@@ -239,7 +239,7 @@
 
 /*
  * Visual styling for dropbutton in the Settings Tray module's off canvas tray.
- * @todo Move to it's own component:
+ * @todo Move to its own component:
  *   https://www.drupal.org/node/1945262.
  */
 
diff --git a/core/scripts/run-tests.sh b/core/scripts/run-tests.sh
index 29367230a49423c7065bd8b92b033384e2108b10..64ae223dd4c7a5366cc4642131a603d923831e78 100755
--- a/core/scripts/run-tests.sh
+++ b/core/scripts/run-tests.sh
@@ -128,7 +128,7 @@
 simpletest_script_reporter_timer_stop();
 
 // Ensure all test locks are released once finished. If tests are run with a
-// concurrency of 1 the each test will clean up it's own lock. Test locks are
+// concurrency of 1 the each test will clean up its own lock. Test locks are
 // not released if using a higher concurrency to ensure each test method has
 // unique fixtures.
 TestDatabase::releaseAllTestLocks();
diff --git a/core/themes/bartik/css/components/block.css b/core/themes/bartik/css/components/block.css
index 48e9f3f81b0108f1949ad0738b46dc712110ef96..0be1a40cd95884bd485f44a15e0444c9b2dda913 100644
--- a/core/themes/bartik/css/components/block.css
+++ b/core/themes/bartik/css/components/block.css
@@ -3,7 +3,7 @@
  * Visual styles for Bartik's blocks.
  */
 
-/* Block has it's own content wrapper. */
+/* Block has its own content wrapper. */
 .block .content {
   margin-top: 10px;
 }