OCB may refer to:

  • OCB mode, a mode of operation for cryptographic block ciphers
  • Oil circuit breaker, a form of circuit breaker using oil as an insulating medium
  • Oklahoma City bombing, a bomb attack on the Alfred P. Murrah Federal Building in downtown Oklahoma City on April 19, 1995
  • Old Country Buffet, a chain of restaurants managed by Buffets, Inc.
  • Operations Coordinating Board (1953—1961), a committee of the United States Executive
  • Óquei Clube de Barcelos, a rink hockey team from Barcelos, Portugal
  • Orange Catholic Bible, a fictional book from the Dune universe created by Frank Herbert
  • Organizational citizenship behavior, a special type of work behavior
  • Ordinary course of business, a term in law covering the usual transactions, customs and practices of a certain business and of a certain firm
  • Orient Commercial Joint Stock Bank (OCB), a large bank located in Vietnam