diff --git a/browser/components/sessionstore/TabState.sys.mjs b/browser/components/sessionstore/TabState.sys.mjs
index 26f5671c849d9b0a126d79b07bc7d3d7870826ec..decc4c975507c9111df78dbc43434fa46d5f5e82 100644
--- a/browser/components/sessionstore/TabState.sys.mjs
+++ b/browser/components/sessionstore/TabState.sys.mjs
@@ -98,6 +98,8 @@ var TabStateInternal = {
       tabData.muteReason = tab.muteReason;
     }
 
+    tabData.zenWorkspace = tab.getAttribute("zen-workspace-id");
+
     tabData.searchMode = tab.ownerGlobal.gURLBar.getSearchMode(browser, true);
 
     tabData.userContextId = tab.userContextId || 0;