A vapor vent valve for venting air and fuel vapor from vehicle fuel tanks comprises a hollow valve body having radial flow ports formed therein, and an axially slidable shutter movable between a valve open position remote from the radial flow ports and a valve closed position covering the radial flow ports. An axially slidable float mounted on the valve body adjacent the shutter lowers and raises the shutter between the valve open and closed positions in response to changes in the tank fuel level. The axial shutter and float structure is unaffected by the radial outflow of air and fuel vapor through the ports.