diff --git a/src/base-apis.js b/src/base-apis.js
index 7f395361a..1d59d9137 100644
--- a/src/base-apis.js
+++ b/src/base-apis.js
@@ -633,6 +633,19 @@ MatrixBaseApis.prototype.acceptGroupInvite = function(groupId, opts = null) {
     return this._http.authedRequest(undefined, "PUT", path, undefined, opts || {});
 };
 
+/**
+ * @param {string} groupId
+ * @return {module:client.Promise} Resolves: Empty object
+ * @return {module:http-api.MatrixError} Rejects: with an error response.
+ */
+MatrixBaseApis.prototype.joinGroup = function(groupId) {
+    const path = utils.encodeUri(
+        "/groups/$groupId/self/join",
+        {$groupId: groupId},
+    );
+    return this._http.authedRequest(undefined, "PUT", path, undefined, {});
+};
+
 /**
  * @param {string} groupId
  * @return {module:client.Promise} Resolves: Empty object