Swimming at the 2011 World Aquatics Championships – Men's 800 metre freestyle

The men's 800 metre freestyle competition of the swimming events at the 2011 World Aquatics Championships was held on July 26 with the heats and July 27 with the final.

Records
Prior to the competition, the existing world and championship records were as follows.

Heats
51 swimmers participated in 7 heats.

Final
The final was held at 18:41.