diff --git a/features/post-meta.feature b/features/post-meta.feature
index a7eacd135f..e8dd92da3c 100644
--- a/features/post-meta.feature
+++ b/features/post-meta.feature
@@ -109,3 +109,33 @@ Feature: Manage post custom fields
     Then STDOUT should be a table containing rows:
       | post_id | meta_key | meta_value         |
       | 1       | foo      |                    |
+
+  Scenario: Make sure WordPress receives the slashed data it expects in meta fields
+    Given a WP install
+
+    When I run `wp post-meta add 1 foo 'My\Meta'`
+    Then STDOUT should not be empty
+
+    When I run `wp post-meta get 1 foo`
+    Then STDOUT should be:
+      """
+      My\Meta
+      """
+
+    When I run `wp post-meta update 1 foo 'My\New\Meta'`
+    Then STDOUT should be:
+      """
+      Success: Updated custom field 'foo'.
+      """
+
+    When I run the previous command again
+    Then STDOUT should be:
+      """
+      Success: Value passed for custom field 'foo' is unchanged.
+      """
+
+    When I run `wp post-meta get 1 foo`
+    Then STDOUT should be:
+      """
+      My\New\Meta
+      """
diff --git a/php/WP_CLI/CommandWithMeta.php b/php/WP_CLI/CommandWithMeta.php
index 0e8a07a39a..26c717c205 100644
--- a/php/WP_CLI/CommandWithMeta.php
+++ b/php/WP_CLI/CommandWithMeta.php
@@ -179,6 +179,7 @@ public function add( $args, $assoc_args ) {
 
 		$object_id = $this->check_object_id( $object_id );
 
+		$meta_value = wp_slash( $meta_value );
 		$success = add_metadata( $this->meta_type, $object_id, $meta_key, $meta_value );
 
 		if ( $success ) {
@@ -221,6 +222,7 @@ public function update( $args, $assoc_args ) {
 		if ( $meta_value === $old_value ) {
 			WP_CLI::success( "Value passed for custom field '$meta_key' is unchanged." );
 		} else {
+			$meta_value = wp_slash( $meta_value );
 			$success = update_metadata( $this->meta_type, $object_id, $meta_key, $meta_value );
 
 			if ( $success ) {