Weir Greenhouse is a historic greenhouse located across the street from the main entrance of Green-Wood Cemetery in Sunset Park, Brooklyn, New York, New York. It was designed by George Curtis Gillespie and built in 1895 by James Weir, Jr., a Brooklyn florist who had been in business for 50 years when he built the greenhouse for the business he operated with his son and grandson. It is a rectangular, wood frame and galvanized iron building with projecting bays and domes in the Victorian commercial style. The main entrance is set at an angle to the street corner and is octagonal in form. The rooftop features an octaginal cupola with a ball finial. Attached to the greenhouse is a one-story brick office structure.
It was listed on the National Register of Historic Places in 1984.
The Weirs continued to operate the business until 1971, when they sold to the McGovern family. The building was designated a New York City Landmark in 1982. On February 2, 2012, the Weir Greenhouse was purchased by the neighboring Green-Wood Cemetery, which plans to preserve the greenhouse and restore elements which have decayed in recent years. By spring, 2015, structural stabilization of the vacant, decayed building was complete, and the project was scheduled to move toward restoration of the building to its 1895 appearance.