PSA is an abbreviation used for a number of different things.
- Prostate specific antigen is a substance that can be detected in the blood of men with prostate cancer.
- In the United Kingdom, the Production Services Association is a union.
- The Paralysis Society of America is a group based on The Paralyzed Veterans Of America except supporting civilians.
- The Pharmaceutical Society of Australia, an organisation for pharmacists.
- In New Zealand, the Public Service Association is a large union for workers in the public sector.
- PSA is a Singaporean shipping company.
- A French company that owns the Peugeot and Citroën brands.
- PSA is used as an abbreviation for Public Service Announcement.
- PSA was an airline that used to fly passenger services inside California and to other nearby Western United States areas during the 1970s and early 1980s. Pacific Southwest Airlines' trademark was a smile drawn under their planes' cockpits.
- pressure-sensitive adhesive