James Speed (March 11, 1812 – June 25, 1887) was an American lawyer, politician, and professor who was in 1864 appointed by Abraham Lincoln to be the United States Attorney General.

He graduated from St. Joseph's College in Bardstown, Kentucky, studied law at Transylvania University and was admitted to the bar at Louisville, in 1833.

After Lincoln's assassination, Speed became increasingly associated with the Radical Republicans and advocated allowing male African Americans to vote.

Disillusioned with the increasingly conservative policies of former Democratic President Andrew Johnson, Speed resigned from the Cabinet in July 1866 and resumed the practice of law.

In 1868, Speed ran for the Republican nomination for Vice President of the United States but the convention instead chose Schuyler Colfax.

Speed also ran for U.S. Representative from Kentucky's 5th District in 1870, to succeed Democrat Asa Grover, who had been accused of disloyalty but was exonerated and finished his only term.

He was elected a 3rd class companion of the Military Order of the Loyal Legion of the United States in recognition of his service to the Union during the Civil War.