diff --git a/modules/field/field.api.php b/modules/field/field.api.php
index 3287dd5..c8518a1 100644
--- a/modules/field/field.api.php
+++ b/modules/field/field.api.php
@@ -677,6 +677,7 @@ function hook_field_is_empty($item, $field) {
  *
  * @see hook_field_widget_info_alter()
  * @see hook_field_widget_form()
+ * @see hook_field_widget_form_alter()
  * @see hook_field_widget_error()
  *
  * @return
@@ -786,6 +787,9 @@ function hook_field_widget_info_alter(&$info) {
  * @see field_widget_field()
  * @see field_widget_instance()
  *
+ * Other modules may alter the form element provided by this function using
+ * hook_field_widget_form_alter().
+ *
  * @param $form
  *   The form structure where widgets are being attached to. This might be a
  *   full form structure, or a sub-element of a larger form.
@@ -836,6 +840,30 @@ function hook_field_widget_form(&$form, &$form_state, $field, $instance, $langco
 }
 
 /**
+ * Alter forms for field widgets provided by other modules.
+ *
+ * @param $element
+ *   The field widget form element as constructed by hook_field_widget_form().
+ * @param $form_state
+ *   An associative array containing the current state of the form.
+ * @param $context
+ *   An associative array containing additional information about the current
+ *   field widget:
+ *   - field: The field structure.
+ *   - instance: The field instance.
+ *   - form: The form structure where widgets are being attached.
+ *     This might be a full form structure, or a sub-element of a larger form.
+ *
+ * @see hook_field_widget_form()
+ * @see hook_form_alter()
+ */
+function hook_field_widget_form_alter(&$element, &$form_state, $context) {
+  if ($context['instance']['widget']['type'] = 'my_autocomplete_type') {
+    $element['#autocomplete_path'] = 'mymodule/path';
+  }
+}
+
+/**
  * Flag a field-level validation error.
  *
  * @param $element
diff --git a/modules/field/field.form.inc b/modules/field/field.form.inc
index 9250a51..7e28bd7 100644
--- a/modules/field/field.form.inc
+++ b/modules/field/field.form.inc
@@ -27,13 +27,13 @@ function field_default_form($entity_type, $entity, $field, $instance, $langcode,
   }
 
   // Let modules alter the widget properties.
-  $context = array(
+  $properties_context = array(
     'entity_type' => $entity_type,
     'entity' => $entity,
     'field' => $field,
     'instance' => $instance,
   );
-  drupal_alter(array('field_widget_properties', 'field_widget_properties_' . $entity_type), $instance['widget'], $context);
+  drupal_alter(array('field_widget_properties', 'field_widget_properties_' . $entity_type), $instance['widget'], $properties_context);
 
   // Collect widget elements.
   $elements = array();
@@ -76,6 +76,19 @@ function field_default_form($entity_type, $entity, $field, $instance, $langcode,
           '#delta' => $delta,
         );
         if ($element = $function($form, $form_state, $field, $instance, $langcode, $items, $delta, $element)) {
+          // Allow modules to alter the field widget form element.
+          $form_context = array(
+            'entity_type' => $entity_type,
+            'entity' => $entity,
+            'form' => $form,
+            'field' => $field,
+            'instance' => $instance,
+            'langcode' => $langcode,
+            'items' => $items,
+            'delta' => $delta,
+          );
+
+          drupal_alter(array($function, 'field_widget_form'), $element, $form_state, $form_context);
           // If we're processing a specific delta value for a field where the
           // field module handles multiples, set the delta in the result.
           // For fields that handle their own processing, we can't make
@@ -193,6 +206,18 @@ function field_multiple_value_form($field, $instance, $langcode, $items, &$form,
             '#weight' => 100,
           );
         }
+        // Allow modules to alter the field widget form element.
+        $context = array(
+          'entity_type' => $instance['entity_type'],
+          'form' => $form,
+          'field' => $field,
+          'instance' => $instance,
+          'langcode' => $langcode,
+          'items' => $items,
+          'delta' => $delta,
+        );
+        drupal_alter(array($function, 'field_widget_form'), $element, $form_state, $context);
+
         $field_elements[$delta] = $element;
       }
     }