Reginald Heber Thomson (usually R.H. Thomson; 1856 – January 7, 1949) was a self-taught American civil engineer. He worked in Washington state, mainly in Seattle, where he became city engineer in 1892 and held the position for two decades. Alan J. Stein wrote that Thomson "probably did more than any other individual to change the face of Seattle" and was responsible for "virtually all of Seattle's infrastructure".