Abstract: A pop-up nozzle for an underground sprinkler system. The nozzle includes a spray head fastened to the top of a hollow stem which is slidably mounted within a cylindrical sleeve. The sleeve is imbedded in the ground, and its lower end is connected to a source of pressurized water. As water flows into the sleeve, the stem and spray move axially within the sleeve so that the spray head projects above ground level and allows water emanating from the spray head to clear ground obstructions. A radial projection on the stem mates with one of a plurality of circumferentially spaced axial grooves in the sleeve to fix the angular position of the spray in a predetermined direction when a unidirectional spray head is used.