Bottom trawling is trawling (towing a trawl, which is a fishing net) along the sea floor.

The scientific community divides bottom trawling into benthic trawling and demersal trawling. Benthic trawling is towing a net at the very bottom of the ocean and demersal trawling is towing a net just above the benthic zone.

Bottom trawling can be contrasted with midwater trawling (also known as pelagic trawling), where a net is towed higher in the water column. Midwater trawling catches pelagic fish such as anchovies, shrimp, tuna and mackerel, whereas bottom trawling targets both bottom living fish (groundfish) and semi-pelagic fish such as cod, squid, halibut and rockfish.

Trawling is done by a trawler, which can be a small open boat with only 30 hp or a large factory trawler with 10,000 hp. Bottom trawling can be carried out by one trawler or by two trawlers fishing cooperatively (pair trawling).