A window sash assembly includes a window sash having an upper rail and at least one side rail that form a corner of the window sash. A slot at the window sash corner opens laterally outwardly from the corner and is defined in part by opposed linear tracks on the upper rail. A tilt latch is disposed in the slot, and includes a housing having opposed sidewalls and outwardly extending ledges overlying the sidewalls slidably received over the tracks on the upper rail. A flexible resilient spring element on each sidewall is spaced from the associated ledge such that the tracks on the rails are slidably received between the ledges and the spring elements.