We report the catalyst-free growth of ZnO nanotips by metalorganic chemical vapor deposition (MOCVD) on various substrates, including c-sapphire, (100) Si, titanium, glass and SiO2. Structural, optical, and electrical properties of ZnO nanotips are investigated. ZnO nanotips are found to be single crystalline and oriented along the c-axis normal to the growth plane. The nanotips exhibit dominant free excitonic transition and enhanced luminescence efficiency with negligible deep-level emission. Controllable in situ Ga doping during MOCVD growth reduces the resistivity of ZnO nanotips. Selective growth of ZnO nanotips has been achieved on patterned Ti/r-Al2O3, SiO2/r-Al2O3, and silicon-on-sapphire (SOS) substrates. It provides the potential to integrate ZnO nanotips and ZnO epitaxial films on a single patterned substrate for various device applications.