Oscar Lapham (June 29, 1837 – March 29, 1926) was an American lawyer and politician from the U.S. state of Rhode Island.

He served as a member of the Rhode Island Senate and the United States House of Representatives.

[7] During the American Civil War, he served as first lieutenant, adjutant and captain in the Twelfth Rhode Island Volunteers.

[8] After the war, he was elected as a companion of the Massachusetts Commandery of the Military Order of the Loyal Legion of the United States.

[16] This article incorporates public domain material from the Biographical Directory of the United States Congress