OSSO was founded by Dr. Rex Head, a medical doctor from Rexburg, Idaho. After adopting two healthy little girls and a young boy with cerebral palsy, Rex and his wife wanted to do more to help children without parents. They visited and gave assistance in orphanages in several countries, but when visiting a girls orphanage in Cuenca, Ecuador, Rex had the feeling that somehow these girls were different. It was like they were his own children. They returned a couple times as a family and then with a group of volunteers from Ricks College.

In 1999, Rex and his wife formed a nonprofit organization that began sending groups of volunteers to serve continually under the name "Semester of International Service" and then "Orphanage Support Services Organization (OSSO)". Since that time, they have expanded to serve over a dozen orphanages in Ecuador with financial support, volunteer support, and consulting support.