A modular vapor-tight light fixture is provided herein which generally includes first and second vapor-tight light modules, and a coupling for connecting the first and second vapor-tight light modules. Each of the vapor-tight light modules includes: a channel housing; a lens secured to the channel housing; a plurality of solid state light generating elements; and, first and second end caps. Each of the channel housings includes first and second rails which each define a mounting channel. The coupling includes mounting strip portions configured such that, with the first and second vapor-tight light modules being adjacent, the mounting strip portions are simultaneously received in the mounting channels of both the first and second vapor-tight light modules. Advantageously, with the subject invention, fully enclosed vapor-tight light modules may be provided at shorter lengths which are connected by the coupling to provide a fixture comparable in length to prior-art vapor-tight light fixtures.