Abstract: A universal test fixture assembly for circuit packs includes a test fixture body, a top guide plate and a bottom guide plate. Each guide plate includes tracks that extend from a front end to a second end of the guide plates and further includes an integrally formed latching channel that runs perpendicular to the tracks. The top guide plate and bottom guide plate are mounted in an opposing and matching relationship such that the circuit pack slidably engages one of the tracks in the top guide plate and a corresponding track in the bottom guide plate and are moveable relative to one another to accommodate circuit packs of varying sizes. The guide plates include tabs which mate with corresponding slots on the test fixture body to prevent misalignment and reduce tolerance build-ups. A second pair of guide plates are attachable to form a two-tiered structure such that two different circuit pack sizes can be accommodated in the same test fixture.