Thomas Andrew Malchow (born August 18, 1976) is a retired American competition swimmer, Olympic gold medalist, and former world record-holder.

At the 1996 Summer Olympics in Atlanta, he received a silver medal for his second-place performance in the men's 200-meter butterfly.

Four years later at the 2000 Summer Olympics in Sydney, he won the gold medal in the men's 200-meter butterfly.

Malchow was also a captain of the U.S. Men's Swimming Team at the 2004 Summer Olympics.

He attended high school in Minnesota at Saint Thomas Academy, graduated from the University of Michigan and was a member of the United States Swimming (USS) Team 'Star'.