Marcelo Chierighini (born 15 January 1991) is a Brazilian competitive swimmer. In the 100 metre freestyle, he was an Olympic finalist at the Rio 2016 Games, and four times in a row a finalist at the World Championships in 2013, 2015, 2017 and 2019. In the 4 x 100 metre freestyle relay, he holds a silver medal at the 2017 World Championships.

At the 2010 FINA World Swimming Championships (25 m) in Dubai, Chierighini, along with César Cielo, Nicholas Santos and Nicolas Oliveira, won the bronze medal in the 4×100-metre freestyle relay with a time of 3:05.74, a South American record, beating the U.S. team.

At the 2011 World Aquatics Championships in Shanghai, China, where he finished 9th in the 4×100-metre freestyle. At the 2011 Summer Universiade, he got a silver medal in the 4×100-metre freestyle relay.

Chierighini swam at the 2012 Summer Olympics in the 4×100-metre medley relay, in which he ranked 15th, and the 4×100-metre freestyle relay, in which he ranked 9th.

In April 2013, at the Maria Lenk Trophy in Brazil, Chierighini swam the seventh-best time of the year in the 50-metre freestyle (21.88 seconds) and fourth-best in the 100-metre freestyle (48.11 seconds). At the 2013 World Aquatics Championships in Barcelona, he finished 7th in the 4×100-metre freestyle, along with Fernando Santos, Nicolas Oliveira and Vinícius Waked. In the 100-metre freestyle, he equalled his personal best in the semifinal, with a time of 48.11 seconds, ranking third for the final, behind Adrian (47.95) and Feigen (48.07). He finished 6th in the final, with a time of 48.28. In the 50-meter freestyle, Cherighini reached the semifinals, where he beat his personal record with a time of 21.84 seconds. However, due to the high level of competition (thirteen swimmers swam times below 22.0 seconds, better than London 2012 when ten swimmers did it), he finished 10th, missing out on the final by ten-hundredths of a second. In the 4×100-metre medley, he finished 12th, along with Leonardo de Deus, Felipe Lima and Nicholas Santos.

At the 2014 Pan Pacific Swimming Championships in Gold Coast, Queensland, Australia, Chierighini won a bronze medal in the Brazilian 4×100-metre freestyle relay, along with João de Lucca, Bruno Fratus and Nicolas Oliveira. He also finished 4th in the 4x100-metre medley relay, along with Guilherme Guido, Felipe França and Thiago Pereira, 8th in the 50-metre freestyle, and 9th in the 100-metre freestyle.

At the 2015 Pan American Games in Toronto, Ontario, Canada, Chierighini won the gold medal in the 4×100-metre medley relay (breaking the Pan American Games record with a time of 3:32.68, along with Guilherme Guido, Felipe França Silva and Arthur Mendes). and in the 4×100-metre freestyle relay (where the team broke the Pan American Games record with a time of 3:13.66, he swam with Matheus Santana, João de Lucca and Bruno Fratus). He also won a bronze medal in the 100-metre freestyle.

At the 2015 World Aquatics Championships in Kazan, Chierighini finished 4th in the Men's 4 × 100 metre freestyle relay, along with Matheus Santana, Bruno Fratus and João de Lucca. César Cielo didn't swim the final - despite participating in the championship, he was feeling shoulder pain on this day. In the Men's 100 metre freestyle, Chierighini achieved his best individual result at the World Championships, finishing in 5th place, with a time of 48.27. He also finished 10th in the Men's 4 × 100 metre medley relay.