A universal adapter for enabling truss foundations to support conventional single-axis trackers. In some cases, the adapter has a main body with an upper portion that presents a standard I-beam interface with pre-drilled holes to interface to a specific single-axis tracker. A pair of connecting portions point down and away from the main body and enable upper leg sections to connect the adapter to a pair of driven screw anchors located below it. The connecting portions may orient the truss so that the rotational axis of the single-axis tracker is aligned with the work point of the truss foundation made from the adapter, upper legs, and driven screw anchors. This will enable to the truss to interface with many different trackers much like conventional plumb-driven H-pile foundations.