Charles Leroy "Roy" (Bob) Mackert (February 2, 1894 – February 12, 1942) was an American football player. He played professional football for the Rochester Jeffersons for one season in 1925. Mackert played college football for Maryland, and returned there in 1935 as the line coach. Mackert was born on February 2, 1894 in Sunbury, Pennsylvania. He attended Lebanon Valley College and then the University of Maryland. He played as a fullback on the Maryland football team during the 1919 and 1920 seasons.