The Tomb of Sayyid Hassan Modarres (Persian: آرامگاه سید حسن مدرس) is located in Kashmar, Iran. It is the burial site of Sayyid Hassan Modarres, a prominent Shi'ite cleric who formerly served as a cabinet representative of the Islamic Consultative Assembly. He was assassinated in 1937, and the mausoleum was built over his grave in 1943 following the forced abdication of Reza Shah Pahlavi.

The mausoleum was built in 1943, after Hassan Modarres' death in 1937, who was poisoned and then died of suffocation. After the exile of Reza Shah Pahlavi, a new tombstone for Hassan Modarres was erected over his grave by locals in an act of honour. A building was eventually built over the grave. Following the Iranian revolution, the new Supreme Leader of Iran, Ruhollah Khomeini, restored the mausoleum, and gave it an extensive rebuild.

The mausoleum was formerly a small building located in the middle of a large garden, which does not exist anymore after the expansion and reconstructions. The present mausoleum was built in the Safavid architectural style. It has four iwans, one on each side, and the mausoleum is topped by a large turquoise dome. Next to the mausoleum is the library of Hassan Modarres.

The grave of Hassan Modarres is located underneath the dome of the mausoleum.

List of mausoleums in Iran