diff --git a/addons/web/static/src/webclient/actions/action_service.js b/addons/web/static/src/webclient/actions/action_service.js
index a48fe3d3721..32d3749fb2c 100644
--- a/addons/web/static/src/webclient/actions/action_service.js
+++ b/addons/web/static/src/webclient/actions/action_service.js
@@ -399,11 +399,15 @@ function makeActionManager(env) {
                 return viewSwitcherEntry;
             });
         const context = action.context || {};
+        let groupBy = context.group_by || [];
+        if (typeof groupBy === "string") {
+            groupBy = [groupBy];
+        }
         const viewProps = Object.assign({}, props, {
             context,
             display: { mode: target === "new" ? "inDialog" : target },
             domain: action.domain || [],
-            groupBy: action.context.group_by || [],
+            groupBy,
             loadActionMenus: target !== "new" && target !== "inline",
             loadIrFilters: action.views.some((v) => v[1] === "search"),
             resModel: action.res_model,
diff --git a/addons/web/static/tests/webclient/actions/window_action_tests.js b/addons/web/static/tests/webclient/actions/window_action_tests.js
index e367bcf152c..727b7abe3af 100644
--- a/addons/web/static/tests/webclient/actions/window_action_tests.js
+++ b/addons/web/static/tests/webclient/actions/window_action_tests.js
@@ -2430,4 +2430,20 @@ QUnit.module("ActionManager", (hooks) => {
         const titleService = webClient.env.services.title;
         assert.strictEqual(titleService.current, '{"zopenerp":"Odoo","action":"Partners"}');
     });
+
+    QUnit.test("action group_by of type string", async function (assert) {
+        assert.expect(2);
+        serverData.views["partner,false,pivot"] = `<pivot/>`;
+        registry.category("services").add("user", makeFakeUserService());
+        const webClient = await createWebClient({ serverData });
+        await doAction(webClient, {
+            name: "Partner",
+            res_model: "partner",
+            type: "ir.actions.act_window",
+            views: [[3, "pivot"]],
+            context: { group_by: "foo" },
+        });
+        assert.containsOnce(webClient, ".o_pivot_view");
+        assert.containsN(webClient, ".o_pivot_view tbody th", 6);
+    });
 });