diff --git a/wp-includes/default-widgets.php b/wp-includes/default-widgets.php
index 68048c3173..8a803a4770 100644
--- a/wp-includes/default-widgets.php
+++ b/wp-includes/default-widgets.php
@@ -660,13 +660,18 @@ class WP_Widget_Recent_Posts extends WP_Widget {
 	}
 
 	function widget($args, $instance) {
-		$cache = wp_cache_get('widget_recent_posts', 'widget');
+		$cache = array();
+		if ( ! $this->is_preview() ) {
+			$cache = wp_cache_get( 'widget_recent_posts', 'widget' );
+		}
 
-		if ( !is_array($cache) )
+		if ( ! is_array( $cache ) ) {
 			$cache = array();
+		}
 
-		if ( ! isset( $args['widget_id'] ) )
+		if ( ! isset( $args['widget_id'] ) ) {
 			$args['widget_id'] = $this->id;
+		}
 
 		if ( isset( $cache[ $args['widget_id'] ] ) ) {
 			echo $cache[ $args['widget_id'] ];
@@ -723,8 +728,12 @@ class WP_Widget_Recent_Posts extends WP_Widget {
 
 		endif;
 
-		$cache[$args['widget_id']] = ob_get_flush();
-		wp_cache_set('widget_recent_posts', $cache, 'widget');
+		if ( ! $this->is_preview() ) {
+			$cache[ $args['widget_id'] ] = ob_get_flush();
+			wp_cache_set( 'widget_recent_posts', $cache, 'widget' );
+		} else {
+			ob_flush();
+		}
 	}
 
 	function update( $new_instance, $old_instance ) {
@@ -807,10 +816,13 @@ class WP_Widget_Recent_Comments extends WP_Widget {
 	function widget( $args, $instance ) {
 		global $comments, $comment;
 
-		$cache = wp_cache_get('widget_recent_comments', 'widget');
-
-		if ( ! is_array( $cache ) )
+		$cache = array();
+		if ( ! $this->is_preview() ) {
+			$cache = wp_cache_get('widget_recent_comments', 'widget');
+		}
+		if ( ! is_array( $cache ) ) {
 			$cache = array();
+		}
 
 		if ( ! isset( $args['widget_id'] ) )
 			$args['widget_id'] = $this->id;
@@ -865,8 +877,11 @@ class WP_Widget_Recent_Comments extends WP_Widget {
 		$output .= $after_widget;
 
 		echo $output;
-		$cache[$args['widget_id']] = $output;
-		wp_cache_set('widget_recent_comments', $cache, 'widget');
+
+		if ( ! $this->is_preview() ) {
+			$cache[ $args['widget_id'] ] = $output;
+			wp_cache_set( 'widget_recent_comments', $cache, 'widget' );
+		}
 	}
 
 	function update( $new_instance, $old_instance ) {
diff --git a/wp-includes/widgets.php b/wp-includes/widgets.php
index 5f2ea1b06a..6295479ca3 100644
--- a/wp-includes/widgets.php
+++ b/wp-includes/widgets.php
@@ -163,6 +163,21 @@ class WP_Widget {
 		return array($this, 'form_callback');
 	}
 
+	/**
+	 * Determine if we're in the Customizer; if true, then the object cache gets
+	 * suspended and widgets should check this to decide whether they should
+	 * store anything persistently to the object cache, to transients, or
+	 * anywhere else.
+	 *
+	 * @since 3.9.0
+	 *
+	 * @return bool True if Customizer is on, false if not.
+	 */
+	function is_preview() {
+		global $wp_customize;
+		return ( isset( $wp_customize ) && $wp_customize->is_preview() ) ;
+	}
+
 	/** Generate the actual widget content.
 	 *	Just finds the instance and calls widget().
 	 *	Do NOT over-ride this function. */
@@ -189,8 +204,21 @@ class WP_Widget {
 			 * @param array     $args     An array of default widget arguments.
 			 */
 			$instance = apply_filters( 'widget_display_callback', $instance, $this, $args );
-			if ( false !== $instance )
-				$this->widget($args, $instance);
+
+			if ( false === $instance ) {
+				return;
+			}
+
+			$was_cache_addition_suspended = wp_suspend_cache_addition();
+			if ( $this->is_preview() && ! $was_cache_addition_suspended ) {
+				wp_suspend_cache_addition( true );
+			}
+
+			$this->widget( $args, $instance );
+
+			if ( $this->is_preview() ) {
+				wp_suspend_cache_addition( $was_cache_addition_suspended );
+			}
 		}
 	}
 
@@ -241,7 +269,16 @@ class WP_Widget {
 
 				$old_instance = isset($all_instances[$number]) ? $all_instances[$number] : array();
 
-				$instance = $this->update($new_instance, $old_instance);
+				$was_cache_addition_suspended = wp_suspend_cache_addition();
+				if ( $this->is_preview() && ! $was_cache_addition_suspended ) {
+					wp_suspend_cache_addition( true );
+				}
+
+				$instance = $this->update( $new_instance, $old_instance );
+
+				if ( $this->is_preview() ) {
+					wp_suspend_cache_addition( $was_cache_addition_suspended );
+				}
 
 				/**
 				 * Filter a widget's settings before saving.
@@ -257,8 +294,9 @@ class WP_Widget {
 				 * @param WP_Widget $this         The current widget instance.
 				 */
 				$instance = apply_filters( 'widget_update_callback', $instance, $new_instance, $old_instance, $this );
-				if ( false !== $instance )
+				if ( false !== $instance ) {
 					$all_instances[$number] = $instance;
+				}
 
 				break; // run only once
 			}