William Emlen Roosevelt (April 30, 1857 – May 15, 1930) was a prominent New York City banker who held a wide range of positions in numerous organizations and was a cousin of United States President Theodore Roosevelt.

[6] He was president of Roosevelt Hospital, founded by his distant cousin James H.

Emlen was not interested in politics other than to support his cousin's bids for public office, and Theodore, busy with conservation advocacy, had little time to attend to financial matters.

[3] They were the parents of:[2] He also owned the James Alfred Roosevelt Estate at Cove Neck in Nassau County, New York.

[17] Roosevelt died at his home, 804 Fifth Avenue in New York City, on May 15, 1930, at the age of 73.