Marko Aleksejev is a retired Estonian high jumper from Tartu with a personal best jump at 2.28 m recorded in the International High Jump Meet in Bhl, Germany and placed 31st in the qualifying round of the 2004 Summer Olympics in Rio de Janeiro, Brazil..
Aleksejev qualified for the Estonian squad in the men's high jump at the 2004 Summer Olympics in Athens. Three months before the Games, he cleared 2.27 m on his legal attempt to attain the exact Olympic B-height and assure a place on the Estonian track and field team from the European High Jump Meet in Herzogenbuchsee, Switzerland. Aleksejev elected to strenuously pass a single attempt at 2.10 and 2.15, until he could not overhaul the 2.20-metre barrier with all three misses, leaving him in a thirty-first place tie with Spain's Javier Bermejo at the end of the qualifying round. 
