The Vassar College Observatory is an astronomical observatory of the private Vassar College, located near the eastern edge of the Poughkeepsie, New York college's campus. Finished in 1865, it was the first building on the college's campus, older even than the Main Building, with which it shares the status of National Historic Landmark. The observatory's significance is due to its association with Maria Mitchell, the first widely known female astronomer in the United States.

Mary Watson Whitney was an American astronomer and was the head of the Vassar College Observatory for 22 years, where 102 scientific papers were published under her guidance.