A cable tray expansion splice plate for connecting first and second cable tray sections end-to-end is disclosed. The splice plate includes an elongate body having a central section, an upper flange section, and a lower flange section. In one embodiment, the lower flange section defines a channel for receiving components of the first and second cable tray sections such that the lower flange section underlies the components. Fastener openings in the central section and the lower flange section receive fasteners to fasten the body to the cable tray sections. These openings include slots which permit the cable tray sections to move relative to one another in a longitudinal direction.