The Mausoleum of Omar Khayyam is a modern mausoleum of white marble erected over Omar Khayyam's tomb located on the south-east of the city of Nishapur, Iran. This mausoleum is a symbol of modern Persian architecture and is part of the national heritage of Iran. This monument was built during the reign of the Pahlavi dynasty and was designed by Hooshang Seyhoun.

The reconstruction of the Mausoleum of Omar Khayyam in Nishapur was commissioned by Reza Shah. Omar's previous tomb was separated from his tomb, and a white marble monument (Current Mausoleum), designed by the Iranian architect Hooshang Seyhoun, was erected over it. This mausoleum became one of the main symbols of the city and one of the known works of the modern Persian architecture. The influence of the architectural design of this mausoleum is visible on the coat of arms of the University of Neyshabur, Neyshabur University of Medical Sciences (NUMS) and other public, civil and private organizations of the city. The construction of the new mausoleum was completed in the year 1963.