A radially locking spray nozzle cap, particularly adapted for quick change of spray tips on agricultural sprayer nozzles, optionally having a spray tip pressed or molded permanently in the bottom thereof. The cap has slightly resilient side walls with inwardly projecting lock lugs at the top, adapted to engage above a retainer flange on a nozzle body. Rotating the cap on the nozzle body engages the lock lugs above the retainer flange and raises the cap sealingly against the nozzle body as radial lock tabs radially distort side walls of the cap until the lock lugs pass over the lock tabs to engage adjacent recesses where the lock tabs hold the cap against counter rotation.