An adjustable hinged corner trowel is formed from hinged plates with a removeably attached handle. Cooperating control arms connect the handle to the hinged plates. The control arms are fixed to the hinged plates and can be fixed relative to each other at the handle by cooperating teeth and grooves. The handle has a threaded member capable of receiving a wing nut to fix the control arms against each other. Thereby, the angle of the hinged plates may be adjusted. The hinged corner trowel establishes both sides of any angled corner at the same time for utilization on drywall or similar materials.