James Andrew Sexton (January 5, 1844 – February 5, 1899) was an American soldier, businessman, and Republican politician from Chicago who served as Commander-in-Chief of the Grand Army of the Republic until his death.

Sexton was born in Chicago in 1844 and enlisted in the Union Army at the outbreak of the American Civil War, rising to captain and serving on the general staff of General William S. Smith.

Politically a Republican, Sexton served as an elector in the 1884 United States presidential election and was appointed postmaster of Chicago by newly elected President Benjamin Harrison in 1889, remaining in office until 1893.

He was also active in veteran's affairs and served as a colonel in the Illinois National Guard.

He was chosen Commander-in-Chief of the Grand Army of the Republic in 1898, a position he filled until his death in Washington, D.C. at the age of 55.