A first embodiment of a torque tube coupler may include an outer body that includes a first abutting surface and a second abutting surface adjacent to the first abutting surface. Set screws may be inserted into one or more channels of the first abutting surface. Tightening the set screws may force the abutting surfaces away from each other and the outer body to press against an inner surface of a torque tube. Another embodiment of the torque tube coupler may include a central ring sized based on a size of a torque tube. The torque tube coupler may also include a set of fingers that extend away from a first side of the central ring and are shaped to flex radially outward. The torque tube coupler may include a core disposed within the set of fingers that, when drawn towards the central ring, causes the fingers to flex radially outwards.