Abstract: A modular solid state high bay lighting fixture is provided herein which includes at least two lighting modules, each including a body configured to define an open channel along one face thereof with a lens or diffuser at least partly overlying each of the open channels. Bottom and upper plates extend between the lighting modules with the upper plate being spaced from, and at least partially overlying, the bottom plate so that a chamber is formed therebetween. The bottom plate is movable relative to the bodies of the lighting module from a first state, where the bottom plate is edge supported, to a second state, where one edge is clear of the bodies allowing the bottom plate to rotate.