Mark Alan Williamson
- Bats Right, Throws Right
- Height 6' 0", Weight 172 lb.
- School Grossmont College, San Diego State University
- Debut April 8, 1987
- Final Game August 4, 1994
- Born July 21, 1959 in Corpus Christi, TX USA
- Pitched the eighth inning of a combined no-hitter along with Bob Milacki (1st-6th), Mike Flanagan (7th) and Gregg Olson (9th) for the Baltimore Orioles on July 13, 1991.