James H. Timberlake (March 22, 1846 – February 21, 1891) was an American law enforcement officer, Civil War soldier, farmer and rancher who served as a deputy U.S. marshal for the Western District of Missouri.

Timberlake is best known for being the chief enforcer and investigator against the James-Younger Gang, beginning in the 1870s, which culminated in the death of the outlaw Jesse James on April 3, 1882, at the hands of Robert Ford.

Timberlake remained at home to help on his family farm until 1864, when he joined the cavalry division of the Army of Missouri, under the command of Colonel Alonzo W. Slayback in the American Civil War.

[1] When the James-Younger Gang rose to prominence in the 1870s, Timberlake teamed up with Kansas City's Police commissioner Henry H. Craig to investigate and pursue the outlaws.

[4] On March 24, 1882, Timberlake detailed a plan he designed in collaboration with Crittenden, which entailed that the Fords would have ten days to apprehend James, or else the pardon and reward would not stand.