Professional fraternities, in the North American fraternity system, are organizations whose primary purpose is to promote the interests of a particular profession and whose membership is restricted to students in that particular field of professional education or study.

The expansion of Greek letter organizations into Canada was an important stage of the North American fraternity movement, beginning in 1879 with the establishment of a chapter of Zeta Psi at the University of Toronto.

Service fraternity or service sorority may refer to any fraternal public service organization, whether college or community-based.

The North American fraternity and sorority system began with students who wanted to meet secretly, usually for discussions and debates not thought appropriate by the faculty of their schools.