Mike Derby (born c. 1957) is an American businessman and politician serving as a member of the South Dakota House of Representatives from the 34th district.
Derby was raised in Rapid City, South Dakota and graduated from Stevens High School.
He earned a Bachelor of Science degree in business administration from the University of South Dakota in 1979.
Derby served as a member of the South Dakota House of Representatives from 1997 to 2002.
During his first tenure, he chaired the Military Affairs Committee and Ellsworth Task Force.