Merlon Lynn Stevenson (October 31, 1923 – April 10, 2021) was an American physicist. He cofounded Luis Walter Alvarez's research group at the Lawrence Berkeley National Laboratory. His first paper presented internationally described proton-generated mesons using results generated by the lab's cyclotron. Among doctoral candidates he advised are George Kalbfleisch, , and Bill Gary. In 1966-1967 he held a visiting professorship at the University of Heidelberg in Germany. Stevenson retired in 1991 and was named professor emeritus. Shortly thereafter he was diagnosed with Parkinson's disease.