Seymour Parker Gilbert (October 13, 1892 - February 23, 1938) was an American lawyer, banker, politician and diplomat.

Gilbert was educated at Rutgers College, graduating at the age of 19, and received a L.L.B.

Under the Young Plan, the Bank for International Settlements was created, nullifying the position of Parker Gilbert.

Gilbert served as Under Secretary of the Treasury from June 1921 – 1923 as well as Agent General of Reparations from October 1924 until May 1930, working with Weimar Germany to ensure loan repayments to America.

His son S. Parker Gilbert, born 1934, was chairman of Morgan Stanley during the 1980s.