The Costume Collection at Reynolda House consists of approximately seven hundred articles of clothing, representing two generations of the Reynolds Family from c.1890 to c.1965. The collection includes morning, afternoon, and evening dresses, along with lingerie, menswear, children's clothes, hats, shoes, and gloves.
Most of the apparel belonged to Katharine Smith Reynolds and her two daughters, Mary Reynolds Babcock and Nancy Susan Reynolds. In 1973 the attic of the historic house was formally opened as an exhibition space for the Costume Collection.
One of the highlights of the collection is the wedding suit of Katharine Reynolds which, according to family tradition, she made herself. The collection also features heavily embroidered and beaded dresses from the 1920s that belonged to the two daughters, as well as their wedding gowns.