Abstract: A patio umbrella support apparatus can be engaged by the mast of a patio umbrella to permit the positioning of the patio umbrella at desired, selected positions on a patio deck built with deck planks spaced apart by a conventional gap. The umbrella support apparatus is formed with an upright support member affixed to a pair of opposing horizontal support flanges that ride on top of the deck surface. A generally vertical anchoring fin is affixed to the support flanges and upright support member to fit within the conventional gap between deck planks. The anchoring fin and the horizontal flanges provide positional stability for the patio umbrella and permit flexibility in the location of the umbrella on the deck. A notch formed in the anchoring fin can receive a deck support cross beam and further limit movement of the umbrella support apparatus relative to the deck.