El Borj Mosque or Mosque of the tower (Arabic: جامع البرج), also known as Sidi Yahia Mosque (Arabic: جامع سيدي يحيى) is a Tunisian mosque in the northern suburb of the Medina of Tunis.

It is located in 1 Hedi Saidi Street near Bab Laassal, one the Medina of Tunis's gates.

[1] The mosque got its name from a tour that is near to it and has the name of the saint Sidi Yahia El Slimani El Yamani.

According to the commemorative plaque at the entrance, it was built with a madrasa during the Hafsid era in the 14th century.

This article about a mosque or other Islamic place of worship in Tunisia is a stub.