Jan Aleksander Kałusowski (born 12 March 2000 in Łódź) is a Polish swimmer specializing in the breaststroke, a medalist at the European Aquatics Championships, and a Polish record holder.

In 2023, at the 2021 Summer Universiade in Chengdu, held in 2023 due to the COVID-19 pandemic,[2] Kałusowski won a silver medal in the 100 m breaststroke, becoming the first Pole to break the one-minute barrier with a time of 59.86.

[3][4] In February 2024, at the 2024 World Aquatics Championships in Doha, Kałusowski finished 16th in the 50 m breaststroke with a time of 27.38.

[5] Four months later, at the 2024 European Aquatics Championships in Belgrade, he won a silver medal in the 4 × 100 m medley relay with teammates Ksawery Masiuk, Jakub Majerski, and Kamil Sieradzki.

[7] In the 100 m breaststroke event, he finished fifth, setting a new Polish record with a time of 59.58, which he had also broken in the semifinals the previous day.