Harry Sewell (Harold Sewell; 1885–??) was a British athlete. He competed in the 3,200 metres steeplechase at the 1908 Summer Olympics in London.
In the first round of the race, Sewell ran a tight race with James Lightbody of the United States, a former Olympic steeplechase champion. Near the very end, Sewell pulled away and won by about ten yards. This qualified him for the final, in which he placed fifth.