diff --git a/macos/Sources/Features/Terminal/TerminalManager.swift b/macos/Sources/Features/Terminal/TerminalManager.swift
index e904630be..e5704c833 100644
--- a/macos/Sources/Features/Terminal/TerminalManager.swift
+++ b/macos/Sources/Features/Terminal/TerminalManager.swift
@@ -95,7 +95,13 @@ class TerminalManager {
     private func createWindow(withBaseConfig base: Ghostty.SurfaceConfiguration?) -> TerminalController {
         // Initialize our controller to load the window
         let c = TerminalController(ghostty, withBaseConfig: base)
-        
+
+        // For new windows, explicitly disallow tabbing with other windows.
+        // This overrides the value of userTabbingPreference. Rationale:
+        // Ghostty provides separate "New Tab" and "New Window" actions so
+        // there's no reason to make "New Window" open in a tab.
+        c.window!.tabbingMode = .disallowed;
+
         // Create a listener for when the window is closed so we can remove it.
         let pubClose = NotificationCenter.default.publisher(
             for: NSWindow.willCloseNotification,