RBO or Rbo may refer to:
- Rock et Belles Oreilles, a Québécois radio, television and stage comedy group
- MTA Regional Bus Operations, the surface transit division of New York's Metropolitan Transportation Authority
- Ragnarok Battle Offline, a computer game
- Reliability-based optimization, a Multidisciplinary design optimization method
- Rubidium oxide, the chemical compound Rb2O
- Robert Brownlee Observatory in Lake Arrowhead, California
- Rule Based Optimization, an SQL Query plan optimization technique
- Red Buttes Observatory near Laramie, Wyoming
- Rang Badalti Odhani
- Rank-biased overlap used in Ranking information