PSIA or psia may refer to: Physical Security Interoperability Alliance, industrial standardization initiative promoting interoperability of IP-enabled security devices Pounds per square inch absolute (including atmospheric pressure) Professional Ski Instructors of America, an organization offering training and certification for U.S. Ski Instructors Philippine Software Industry Association Paris School of International Affairs Private Schools Interscholastic Association Palm Springs International Airport Public Security Intelligence Agency, the national intelligence agency of Japan