APA may stand for:

• Administrative Procedure Act, an American statute controlling government agency actions.
• American Payroll Association
• Amateur Press Association
• American Philosophical Association
• American Planning Association
• American Psychiatric Association
• American Psychological Association, see also APA style
• American Psychopathological Association
• Antagonist Perpetrated Aggression see Tactical combat for APA Tactical Combat Directive
• Apache Railway (AAR reporting mark APA)
• Asian Pacific American
• Australian Progressive Alliance
• Auto-port Aggregation is a HP-brand of Port trunking products.
• Acolytes Protection Agency, the stage name of a former professional wrestling tag team in World Wrestling Entertainment made up of Bradshaw (John Layfield) and Faarooq (Ron Simmons)
• Southern Athabaskan languages (excluding Navajo) (ISO 639 alpha-3, apa)

Apa is the name of a deity in Hinduism.