Springside was the estate of Matthew Vassar in Poughkeepsie, New York, United States. It is located on Academy Street just off US 9. Detailed plans for a landscape, villa, and complex of farm buildings were drawn up by the influential Andrew Jackson Downing with assistance of Calvert Vaux prior to the former's death. The landscaping was completed and remains Downing's most intact surviving landscape, but only a few of the buildings he planned were ever built; most have since been lost to fire and structural failure. A cottage where Vassar resided was dismantled and removed in the mid-1970s. Its facade is on display in the New York State Museum.

Matthew Vassar was an English-born American brewer, merchant and philanthropist. He founded Vassar College, a women’s college, in 1861. He was a cousin of John Ellison Vassar. The city of Vassar, Michigan, is named after him.