Herein disclosed is a sprinkler valve on/off key that includes a light source therein. The sprinkler valve on/off key includes a gripping member which is of a shape and size to mate with a standard sprinkler head/valve. The light source is housed within the gripping member and when the light source is energized the light illuminates the area around the gripping member and the sprinkler head assembly. Whereby, the workman can visually see and easily manipulate the sprinkler head/valve assembly between the on and off position.