James Marion Baker (August 18, 1861 – November 21, 1940)[1] was an American political figure, who held the position of Secretary of the United States Senate from 1913 to 1919.

Baker was born in South Carolina, and came to serve as the assistant librarian of the United States Senate.

At the retaking of the Senate by the Republican Party in 1919, Baker was replaced by George A. Sanderson, and President Woodrow Wilson appointed Baker deputy commissioner of internal revenue.

In 1931, Baker retired to assist with Franklin D. Roosevelt's presidential campaign.

Baker later became a minister to Thailand in the Roosevelt administration, until retiring due to poor health in 1937.