Martin Luther Smith (September 9, 1819 – July 29, 1866) was an American soldier and civil engineer, serving as a major general in the Confederate States Army.

Smith was one of the few Northern-born generals to fight for the Confederacy, as he had served most of his early military career in the South with the United States Army's topographical engineers, marrying a native of Athens, Georgia.

He served as an engineer during the Mexican–American War, and was brevetted for his performance in mapping the valley of Mexico City prior to Winfield Scott's assaults.

He served under General David Twiggs at New Orleans and commanded a brigade of infantry while helping plan the defenses of the city.

He remained in Mobile until the city fell to Union forces, and then returned home to Athens, where he surrendered in May 1865.

Smith moved to Savannah, Georgia, soon after the war ended and established a civil engineering company.