diff --git a/includes/bootstrap.inc b/includes/bootstrap.inc
index 5556f38..17c698a 100644
--- a/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -279,7 +279,7 @@ define('DRUPAL_PHP_FUNCTION_PATTERN', '[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*'
  * means that assigning an offset via arrayAccess will only apply while the
  * object is in scope and will not be written back to the persistent cache.
  * This follows a similar pattern to static vs. persistent caching in
- * procedural code. Extending classes may wish to alter this behaviour, for
+ * procedural code. Extending classes may wish to alter this behavior, for
  * example by overriding offsetSet() and adding an automatic call to persist().
  *
  * @see SchemaCache
diff --git a/includes/form.inc b/includes/form.inc
index 201e147..585456b 100644
--- a/includes/form.inc
+++ b/includes/form.inc
@@ -3318,7 +3318,7 @@ function form_process_tableselect($element) {
     $value = is_array($element['#value']) ? $element['#value'] : array();
   }
   else {
-    // Advanced selection behaviour make no sense for radios.
+    // Advanced selection behavior make no sense for radios.
     $element['#js_select'] = FALSE;
   }
 
diff --git a/modules/filter/filter.module b/modules/filter/filter.module
index d7f86c8..5452ea1 100644
--- a/modules/filter/filter.module
+++ b/modules/filter/filter.module
@@ -1109,7 +1109,7 @@ function filter_dom_serialize_escape_cdata_element($dom_document, $dom_element,
       $embed_suffix = "\n{$comment_start}--><!]]>{$comment_end}\n";
 
       // Prevent invalid cdata escaping as this would throw a DOM error.
-      // This is the same behaviour as found in libxml2.
+      // This is the same behavior as found in libxml2.
       // Related W3C standard: http://www.w3.org/TR/REC-xml/#dt-cdsection
       // Fix explanation: http://en.wikipedia.org/wiki/CDATA#Nesting
       $data = str_replace(']]>', ']]]]><![CDATA[>', $node->data);
diff --git a/modules/node/node.module b/modules/node/node.module
index 2614c41..57133c6 100644
--- a/modules/node/node.module
+++ b/modules/node/node.module
@@ -2949,7 +2949,7 @@ function node_access($op, $node, $account = NULL) {
       return $result;
     }
     elseif (is_object($node) && $op == 'view' && $node->status) {
-      // If no modules implement hook_node_grants(), the default behaviour is to
+      // If no modules implement hook_node_grants(), the default behavior is to
       // allow all users to view published nodes, so reflect that here.
       $rights[$account->uid][$cid][$op] = TRUE;
       return TRUE;
diff --git a/modules/simpletest/tests/form.test b/modules/simpletest/tests/form.test
index df8d3f2..2f5a9cd 100644
--- a/modules/simpletest/tests/form.test
+++ b/modules/simpletest/tests/form.test
@@ -666,12 +666,12 @@ class FormsElementsLabelsTestCase extends DrupalWebTestCase {
     $this->assertTrue(isset($elements[0]), t("Label 0 found radios."));
 
     // Exercise various defaults for checkboxes and modifications to ensure
-    // appropriate override and correct behaviour.
+    // appropriate override and correct behavior.
     $elements = $this->xpath('//input[@id="edit-form-checkbox-test"]/following-sibling::label[@for="edit-form-checkbox-test" and @class="option"]');
     $this->assertTrue(isset($elements[0]), t("Label follows field and label option class correct for a checkbox by default."));
 
     // Exercise various defaults for textboxes and modifications to ensure
-    // appropriate override and correct behaviour.
+    // appropriate override and correct behavior.
     $elements = $this->xpath('//label[@for="edit-form-textfield-test-title-and-required"]/child::span[@class="form-required"]/parent::*/following-sibling::input[@id="edit-form-textfield-test-title-and-required"]');
     $this->assertTrue(isset($elements[0]), t("Label precedes textfield, with required marker inside label."));
 
diff --git a/modules/user/user.test b/modules/user/user.test
index b5b64d6..1a11afc 100644
--- a/modules/user/user.test
+++ b/modules/user/user.test
@@ -1554,7 +1554,7 @@ class UserBlocksUnitTests extends DrupalWebTestCase {
 }
 
 /**
- * Test case to test user_save() behaviour.
+ * Test case to test user_save() behavior.
  */
 class UserSaveTestCase extends DrupalWebTestCase {
 
@@ -1643,7 +1643,7 @@ class UserCreateTestCase extends DrupalWebTestCase {
 }
 
 /**
- * Test case to test user_save() behaviour.
+ * Test case to test user_save() behavior.
  */
 class UserEditTestCase extends DrupalWebTestCase {