Alfred Morrison Lay (May 20, 1836 – December 8, 1879) was a U.S. Representative from Missouri.
He was admitted to the bar in 1857 and commenced practice in Jefferson City, Missouri.
Enlisted as a private in the Missouri State Guard and was subsequently promoted to the rank of major.
He served as captain of ordnance, Confederate States Army.
Lay was elected as a Democrat to the Forty-sixth Congress and served from March 4, 1879, until his death in Washington, D.C., on December 8, 1879.