Saint Jacob's Church, Medieval parish church in Leuven, Belgium

Saint Jacob's Church is a stone church in Leuven with a Romanesque west tower of white limestone built between 1220 and 1230, topped by a slender slate spire. Its three-aisled Gothic nave, transept by Matheus de Layens (1457–1488), two side chapels and a classicist brick choir (1785) measure 50 by 20 metres. The tower's round-arched sound holes and walled-up west portal rosette remain visible.

Built between 1220 and 1235 as a Romanesque church, it lost all but its tower, probably to a lightning strike. A new nave rose against the tower between 1290 and 1300. Matheus de Layens, architect of Leuven's town hall, built the transept from 1457 to 1488 and was buried here. The choir was rebuilt in brick in 1785 in classicist style.

The church is one of Leuven's "Seven Wonders" because its bell hangs outside the tower in a bell dormer rather than inside the belfry. Legend says the bell was not consecrated and so could not be hung in the tower. It has counted among the wonders since 1478, and such external striking bells are rare in Belgium.

The church has been closed to the public since 1963 due to stability problems. Since 2024 it has been used for trial community projects for local residents, while the city studies the roof structure ahead of a restoration. The parish now worships in the Goudsbloemstraat.

One of the Seven Wonders of Leuven since 1478: a bell hangs not inside the tower but in an external bell turret on its wall. Legend says it was refused a place in the belfry because it had never been consecrated. Such external striking bells are rare in Belgium, unlike in Germany.