Tour Saint-Jacques (French: [tuʁ sɛ̃ʒak], 'Saint James's Tower') is a monument located in the 4th arrondissement of Paris, France, on the Rive Droite.

The tower's rich decoration reflects the wealth of its patrons, the wholesale butchers of the nearby Les Halles market.

A relic of the saint preserved in the church linked it the more strongly and in modern times occasioned its listing in 1998 as a World Heritage Site by UNESCO among the sites and structures marking the chemins de Compostelle, the pilgrimage routes in France that led like tributaries of a great stream headed towards Santiago in the northwest of Spain.

A statue of Blaise Pascal is located at the base of the tower, commemorating the experiments on atmospheric pressure, though it is debated whether they were performed here or at the church of Saint-Jacques-du-Haut-Pas.

Recent findings show that most of the stone and its ornamentation originates from the late-medieval era of the tower's construction, and was not added by the 19th-century restorers.