A fluorescent tube retrofit luminaire includes a lamp, a light guide, and a heat dissipating frame. The lamp may include a bi-pin base, middle structure, and outer structure, which may include a light-emitting diode (LED)-based light source in thermal communication with a finned heat sink section of the middle structure. Light emitted from the light source may be distributed generally along the length and/or width of the light guide. A bi-pin connector in the light guide may attach the luminaire to a first fluorescent socket. The bi-pin base may be received by a mounting aperture in the light guide before anchoring the luminaire to a second fluorescent socket using a pin-lock. The heat dissipating frame may be in thermal communication with both the light guide and the heat sink section of the lamp.