Mark Andrew Reynolds (born August 3, 1983, in Pikeville, Kentucky) is a third baseman/first baseman in Major League Baseball who plays for the Arizona Diamondbacks. He is nicknamed "The Sheriff".

He is 6' 1" and weighs 220 pounds. He is known both for his power-hitting abilities and for his record-breaking strike out totals.

Reynolds attended First Colonial High School in Virginia Beach, Virginia, and the University of Virginia, playing primarily shortstop. Reynolds was drafted in the 16th round (476th overall) of the 2004 Major League Baseball Draft.