A universal mounting system for a light fixture is disclosed. The system includes a channel adapted to be secured proximate a top end of a light pole, a rotatably adjustable knuckle, a flange disposed on a first end of the knuckle and configured to slidingly engage and seat within the channel, and a mounting plate disposed on a second end of the knuckle and configured to secure to the light fixture. The knuckle includes a first annular portion, where the flange is secured to a periphery of the first annular portion. In addition, the knuckle includes a second annular portion, where the mounting plate is secured to a periphery of the second annular portion and configured to engage the first annular portion and rotate relative to the first annular portion to move the mounting plate to a desired angle to the light pole.