The Swiss National Museum said a probe into its origins found the "Lerber Lerche" goblet was bought in 1937 at a sale of items belonging to German-American collector Emma Budge and held months after her death.
The proceeds from the auction went to a bank account blocked by the Nazis, preventing the owners from benefiting.
"Research by the MNS and the Bureau on Looted Art, together with a representative of the executor of Emma Budge's estate, allowed us to clarify the precise circumstances of the acquisition," said a statement from the Federal Office of Culture.
It said the goblet, which features a lark, was being returned in line with an international accord on Nazi-looted art.
Under a 1998 agreement known as the Washington Principles, 44 countries pledged to identify Nazi-confiscated art in museum collections and attempt to return the works to their rightful owners.
Budge (1852-1937) lived in Hamburg and the United States with her banker husband Henry.
Her private collection, including paintings, furniture and porcelain, is reportedly one of the largest auctioned during the Nazi era.