diff --git a/externs/olx.js b/externs/olx.js
index b617b5143d..a5c44d0e30 100644
--- a/externs/olx.js
+++ b/externs/olx.js
@@ -6695,6 +6695,7 @@ olx.source.CartoDBOptions.prototype.account;
  *     cacheSize: (number|undefined),
  *     crossOrigin: (null|string|undefined),
  *     logo: (string|olx.LogoOptions|undefined),
+ *     projection: (ol.ProjectionLike|undefined),
  *     reprojectionErrorThreshold: (number|undefined),
  *     url: !string,
  *     tierSizeCalculation: (string|undefined),
@@ -6739,6 +6740,14 @@ olx.source.ZoomifyOptions.prototype.crossOrigin;
 olx.source.ZoomifyOptions.prototype.logo;
 
 
+/**
+ * Projection.
+ * @type {ol.ProjectionLike|undefined}
+ * @api
+ */
+olx.source.ZoomifyOptions.prototype.projection;
+
+
 /**
  * Maximum allowed reprojection error (in pixels). Default is `0.5`.
  * Higher values can increase reprojection performance, but decrease precision.
diff --git a/src/ol/source/zoomify.js b/src/ol/source/zoomify.js
index 4b4bb889e0..8225d40da2 100644
--- a/src/ol/source/zoomify.js
+++ b/src/ol/source/zoomify.js
@@ -113,6 +113,7 @@ ol.source.Zoomify = function(opt_options) {
     cacheSize: options.cacheSize,
     crossOrigin: options.crossOrigin,
     logo: options.logo,
+    projection: options.projection,
     reprojectionErrorThreshold: options.reprojectionErrorThreshold,
     tileClass: ol.source.Zoomify.Tile_,
     tileGrid: tileGrid,