PSO may refer to:

Orchestras

  • Pacific Symphony Orchestra
  • Peoria Symphony Orchestra
  • Pittsburgh Symphony Orchestra
  • Plano Symphony Orchestra
  • Portland Symphony Orchestra
  • Perth Symphony Orchestra

Science and technology

  • Particle swarm optimization, a swarm intelligence optimization technique
  • Password Settings Object, used in Windows Active Directory environments
  • Phase-shift oscillator, an electronic circuit that generates sine waves
  • Projective special orthogonal group
  • Protocol Support Organization, one of the three initial components of ICANN, later disbanded
  • PSO J318.5-22, a rogue planet discovered in 2013
  • Proximal subungual onychomycosis, a type of nail infection.

Other uses

  • Pakistan State Oil
  • Patient safety organization
  • Paysite operator, the operator of a paysite, typically pornographic
  • Peace Support Operations, a military term used by NATO
  • Penalty shootout, a method of determining a winner in sports matches which would have otherwise been drawn or tied
  • Phantasy Star Online, a series of online role-playing video games
  • Phantasy Star Online, the first game in the series
  • Phone sex operator, a person who provides phone sex service
  • Producers Sales Organization, an independent motion picture production and distribution company
  • Protective services officer, a member of police in Australia who performs policing duties at specific locations
  • Psoriasis, an autoimmune disease
  • PSO-1, a Soviet telescopic sight
  • Public Safety Officer, another name for police, firefighters, ambulance crews and other providing safety services in the U.S.
  • Public Service Company of Oklahoma
  • Public service obligation, a form of state subsidy for transport links which are not commercially viable
  • Puro Sangue Orientale, a breed of horse in Italy
  • The FAA LID code for Stevens Field airport in Archuleta County, Colorado, United States
  • The IATA code for Antonio Nariño Airport, serving the Colombian city of Pasto
  • Personal Security Officers
  • Provider Services Operations, a team at the National Marrow Donor Program