George Bunker Chapman (June 10, 1925 – September 7, 2016) was a professor and a pioneer in research of cell biology and ultrastructure using transmission-light and transmission electron microscopy. He was the first person to see the interior structure of four bacterium species in electron micrographs he produced, described in his Ph.D. dissertation completed in 1953. As a professor, he changed the lives of hundreds of students, colleagues, and others through his mentorship.