The Union Temple of Brooklyn is a Reform synagogue located at 17 Eastern Parkway between Underhill Avenue and Plaza Street East in the Prospect Heights neighborhood of Brooklyn, New York City, across the street from the Brooklyn Public Library, the Brooklyn Museum, and the Brooklyn Botanical Gardens. It is the result of the merger of two nineteenth century congregations, K. K. Beth Elohim and Temple Israel. In 2015 it was listed on the National Register of Historic Places.