diff --git a/internal/cmd/down.go b/internal/cmd/down.go
index d31a783d..5215ab00 100644
--- a/internal/cmd/down.go
+++ b/internal/cmd/down.go
@@ -36,11 +36,13 @@ This is useful for:
 var (
 	downQuiet bool
 	downForce bool
+	downAll   bool
 )
 
 func init() {
 	downCmd.Flags().BoolVarP(&downQuiet, "quiet", "q", false, "Only show errors")
 	downCmd.Flags().BoolVarP(&downForce, "force", "f", false, "Force kill without graceful shutdown")
+	downCmd.Flags().BoolVarP(&downAll, "all", "a", false, "Also kill the tmux server")
 	rootCmd.AddCommand(downCmd)
 }
 
@@ -96,6 +98,16 @@ func runDown(cmd *cobra.Command, args []string) error {
 		printDownStatus("Daemon", true, "not running")
 	}
 
+	// 5. Kill tmux server if --all
+	if downAll {
+		if err := t.KillServer(); err != nil {
+			printDownStatus("Tmux server", false, err.Error())
+			allOK = false
+		} else {
+			printDownStatus("Tmux server", true, "killed")
+		}
+	}
+
 	fmt.Println()
 	if allOK {
 		fmt.Printf("%s All services stopped\n", style.Bold.Render("✓"))
diff --git a/internal/tmux/tmux.go b/internal/tmux/tmux.go
index 90cd73d4..f08ae719 100644
--- a/internal/tmux/tmux.go
+++ b/internal/tmux/tmux.go
@@ -80,6 +80,15 @@ func (t *Tmux) KillSession(name string) error {
 	return err
 }
 
+// KillServer terminates the entire tmux server and all sessions.
+func (t *Tmux) KillServer() error {
+	_, err := t.run("kill-server")
+	if errors.Is(err, ErrNoServer) {
+		return nil // Already dead
+	}
+	return err
+}
+
 // HasSession checks if a session exists.
 func (t *Tmux) HasSession(name string) (bool, error) {
 	_, err := t.run("has-session", "-t", name)