The Rialto Bridge (Italian: Ponte di Rialto) is one of the four bridges spanning the Grand Canal in Venice, Italy. It is the oldest bridge across the canal, and was the dividing line for the districts of San Marco and San Polo.

The first dry crossing of the Grand Canal was a pontoon bridge built in 1181 by Nicolò Barattieri. It was called the Ponte della Moneta, presumably because of the mint that stood near its eastern entrance.

The development and importance of the Rialto market on the eastern bank increased traffic on the floating bridge, so it was replaced in 1255 by a wooden bridge. This structure had two inclined ramps meeting at a movable central section, that could be raised to allow the passage of tall ships. The connection with the market eventually led to a change of name for the bridge. During the first half of the 15th century two rows of shops were built along the sides of the bridge. The rents brought an income to the State Treasury, which helped maintain the bridge.

Maintenance was vital for the timber bridge. It was partly burnt in the revolt led by Bajamonte Tiepolo in 1310. In 1444 it collapsed under the weight of a crowd watching a boat parade and it collapsed again in 1524.

The idea of rebuilding the bridge in stone was first proposed in 1503. Several projects were considered over the following decades. In 1551 the authorities requested proposals for the renewal of the Rialto Bridge, among other things. Plans were offered by famous architects such as Jacopo Sansovino, Palladio and Vignola, but all involved a Classical approach with several arches, which was judged inappropriate to the situation. Michelangelo also was considered as designer of the bridge.