Mark Gerald Esser (born April 1, 1956) is a former professional baseball pitcher. He appeared in two games in Major League Baseball, one week apart, in 1979 for the Chicago White Sox.
He was selected by the Baltimore Orioles in the 20th round of the 1975 MLB Draft out of Roy C. Ketcham High School in Wappinger, New York, and again by the Chicago White Sox in the 8th round of the 1977 MLB Draft out of Miami Dade College.
He was assigned to the Gulf Coast League to begin his professional career.
Esser made his Major League debut on April 22, 1979, against the Cleveland Indians at Cleveland Stadium. He pitched 1.1 scoreless innings in relief of Francisco Barrios. Seven days later, he pitched in the second and final Major League game of his career. Esser faced four Texas Rangers batters at Comiskey Park and retired only one of them, allowing three earned runs on one hit and two walks.
On August 2, 1982, he and Bill Atkinson combined to throw a no-hitter for the Glens Falls White Sox. It would be his final season in professional baseball.