Thomas Stachewicz (born 5 December 1965) is a former freestyle and backstroke swimmer,[1] who represented Australia at three Summer Olympics.

At the 1986 Commonwealth Games in Edinburgh, Stachewicz was part of the gold medal-winning men's 4×200-metre freestyle relay team.

Later that year he competed in the 1986 World Swimming Championships in Madrid, where he was part of the 4×200-metre freestyle relay team that finished fourth.

At 1988 Summer Olympics in Seoul, Stachewicz swam well below his best in the men's 200-metre freestyle heats, qualifying only for the B Final, where he finished 3rd in 1 minute 50.83 seconds.

This time ranked him second all-time Australian in the 200-metre freestyle behind Duncan Armstrong's world record from earlier in the meet.