Driven by the need to promote STEM education in the Philippines and to foster fellowship among alumni across the world, a group of alumni of the Philippine Science High School (PSHS) based in North America who came from different  graduating classes that spanned several decades, sought recognition as the first international chapter of the PSHS National Alumni Association (PSHSNAA) and established a nonprofit organization called the Philippine Science High School (PSHS) International Alumni Foundation, Inc., also known as "Pisayian". Pisayian is a nonprofit organization recognized by the IRS under section 501(c)(3).

Membership is open to alumni from any campus of the PSHS system
who are either currently or formerly based in North America.