Adhai Din Ka Jhonpra (literally "shed of 2½ days") is a mosque in the Ajmer city of Rajasthan, India. It was commissioned by Qutb-ud-Din-Aibak, on orders of Muhammad Ghori, in 1192 CE. It was completed in 1199 CE, and further beautified by Iltutmish of Delhi in 1213 CE.

The mosque was constructed on the remains of a Sanskrit college, with materials from destroyed Hindu and Jain temples. It is one of the oldest mosques in India, and the oldest surviving monument in Ajmer.

An early example of the Indo-Islamic architecture, most of the building was constructed by Hindu masons, under the supervision of Afghan managers. The site is now maintained by the Archaeological Survey of India (ASI).