PFO

PFO may refer to:
 * Patent foramen ovale - a blood-flow pathway between a human heart's atriums, normally naturally closed after birth
 * Personal Freedom Outreach - an Evangelical organization opposing cults
 * Pittsburgh Film Office
 * IATA code for Paphos International Airport
 * Pathfinder Roleplaying Game - online version
 * Persistent Felony Offender - a defendant accused under a three-strikes law
 * Hong Kong's Public Finance Ordinance.