San Pietro alle Scale, Roman Catholic church in Siena, Italy.

San Pietro alle Scale is a single-nave parish church on via San Pietro in Siena, rebuilt in late-Baroque style between the late 17th and early 18th centuries. Its brick and plaster facade, completed in 1706, has a portal topped by a relief of Saint Peter in Glory among Angels. The interior is defined by altars decorated in plaster and stucco.

The church was originally built in the 12th century as a Romanesque structure and later completely transformed into Baroque style during the 17th century. A bell tower was added in 1699, altering the building's appearance.

The church is one of two in Siena dedicated to St Peter, the other being San Pietro alla Magione. Its name, "alle Scale," refers to the steps (scale) of via San Pietro where it stands. The 1610 altarpiece by Francesco Rustici was painted for the Compagnia di San Giovanni Evangelista before reaching this church.

The church stands on via San Pietro in the Terzo di Città, a short walk from the Piazza del Campo. The single nave and side altars are at street level with no steps at the entrance. It is an active parish, so visits are best timed outside Mass.

A fresco fragment near the entrance depicts Saint Catherine painted by Liberale da Verona around 1470. This work survived the building's many renovations and remains visible to visitors today.