Marko Aleksejev is a retired Estonian high jumper. He was selected to compete for the Estonian squad in the men's high jump at the 2004 Summer Olympics, and also trained throughout his athletic career for Audentese Sport Club in Tallinn, under his personal coach Allan Eleranna. In 2005, Aleksejev recorded his personal best jump at 2.28 m from the International High Jump Meet in Bühl, Germany.