Louis Dijour Smullin (February 5, 1916 - June 4, 2009) was an American electrical engineer who spend most of his career at the Massachusetts Institute of Technology (MIT).

He is best known for his work with Giorgio Fiocco to measure the distance to the Moon using a ruby laser in 1962, shortly after that device was invented.

At the Ohio Brass Company in Barberton, he spent two years performing high voltage tests on transmission-line insulators and radio interference.

[2] After the outbreak of war, in 1940 he moved to the Scintilla Magneto Division of Bendix Aviation in Sidney, New York, where Smullin designed test instruments for ignition systems.

The group also developed methods for testing transceiver microwave tubes at over 3 GHz and designed most radar duplexers until the end of the war.

He was also a member of the American Society of Arts and Sciences, the National Academy of Engineering, Eta Kappa Nu and Sigma Xi.

With his wife, Ruth Frankel, he was the father of the sculptor Frank Smullin,[6] and the grandfather of actor, author, and musician Andras Jones.