diff --git a/classes.fields.php b/classes.fields.php
index 506b7c3c..ecffea34 100644
--- a/classes.fields.php
+++ b/classes.fields.php
@@ -1653,6 +1653,7 @@ public function get_default_args() {
 				'default_zoom'                => '8',
 				'string-marker-title'         => esc_html__( 'Drag to set the exact location', 'cmb' ),
 				'string-gmaps-api-not-loaded' => esc_html__( 'Google Maps API not loaded.', 'cmb' ),
+				'google_api_key'              => '',
 			)
 		);
 	}
@@ -1661,7 +1662,22 @@ public function enqueue_scripts() {
 
 		parent::enqueue_scripts();
 
-		wp_enqueue_script( 'cmb-google-maps', '//maps.google.com/maps/api/js?libraries=places' );
+		$maps_src = '//maps.google.com/maps/api/js?libraries=places';
+
+		// Check for our key with either a field argument or constant.
+		if ( ! empty( $this->args['google_api_key'] ) ){
+			$key = $this->args['google_api_key'];
+		} elseif ( defined( 'CMB_GAPI_KEY' ) ) {
+			$key = CMB_GAPI_KEY;
+		}
+
+		// Only add the key argument if it's been set.
+		if ( ! empty( $key ) ) {
+			$maps_src = add_query_arg( 'key', $key, $maps_src );
+		}
+
+		// Enqueue our scripts.
+		wp_enqueue_script( 'cmb-google-maps', $maps_src );
 		wp_enqueue_script( 'cmb-google-maps-script', trailingslashit( CMB_URL ) . 'js/field-gmap.js', array( 'jquery', 'cmb-google-maps' ) );
 
 		wp_localize_script( 'cmb-google-maps-script', 'CMBGmaps', array(
diff --git a/example-functions.php b/example-functions.php
index eb18a71c..8339f11c 100644
--- a/example-functions.php
+++ b/example-functions.php
@@ -44,7 +44,7 @@ function cmb_sample_metaboxes( array $meta_boxes ) {
 
 		array( 'id' => 'field-22', 'name' => 'Color', 'type' => 'colorpicker' ),
 
-		array( 'id' => 'field-23', 'name' => 'Location', 'type' => 'gmap' ),
+		array( 'id' => 'field-23', 'name' => 'Location', 'type' => 'gmap', 'google_api_key' => '{CUSTOM_KEY}' ),
 
 		array( 'id' => 'field-24', 'name' => 'Title Field', 'type' => 'title' ),
 
diff --git a/readme.md b/readme.md
index 41443058..9cbac657 100644
--- a/readme.md
+++ b/readme.md
@@ -59,7 +59,7 @@ See [CONTRIBUTING.md](https://github.com/humanmade/Custom-Meta-Boxes/blob/master
 * Add hide_on field argument
 * Add Composer support
 * Enhancement - enable for attachments
-* Fix bug with unnatached images on custom post types
+* Fix bug with unattached images on custom post types
 * Fix error in WYSIWYG
 * Fix fields not getting correctly initialized if meta box is collapsed on page load
 * Fix bug with page-template restricted meta boxes showing if the post hasn't been saved at all.