A luminaire with a tool-less assembly feature that enhances ease of installation and serviceability in the field. The luminaire's housing defines a compartment accessible via a window adjacent a pair of opposed shoulders. The luminaire further includes a lighting module dimensioned to be received and retained in the window in an interference fit with the shoulders. The lighting module may include an LED module/light guide plate and/or an LED refractor assembly/LED gear tray. A resilient member is supported on the housing in position to abut the lighting module and deflect during insertion of the lighting module through the window, and to at least partially resile to maintain the lighting module against the shoulders in an operative position on the housing. Further, the resilient member is positioned to deflect during removal and to resile to tilt or otherwise assist in ejecting the lighting module from the housing during tool-less disassembly.