John A. Miller (born August John Mueller in 1872, Homewood, Illinois - died June 24, 1941, Houston, Texas) was a roller coaster designer and builder. He held over 100 patents, many of which were for roller coaster safety devices (e.g. the safety chain dog). For a time in his early career, he worked as a consultant to the Philadelphia Toboggan Company. He designed over 60 coasters in his lifetime.