Harold Marshall Sylvester Richards Sr. (August 28, 1894 – April 24, 1985), commonly known as H. M. S. Richards, was a well-known Seventh-day Adventist evangelist and author. Born in Iowa, he is most famous for founding the Voice of Prophecy radio ministry and was a pioneer in religious radio broadcasting. His ministry inspired broadcasts in 36 languages on more than 1,100 stations, and Bible courses in 80 languages offered by 144 correspondence schools.