Katarzyna (Kasia) Nosowska (born August 30, 1971, Szczecin) is the lead singer of the Polish rock band Hey. She is also known for her solo career, which in contrast to Hey's guitar-driven rock delves more into electronica. Apart from penning Hey's lyrics, she is also a columnist in several Polish magazines.

She received many awards and holds the record for the largest number of Fryderyk awards, including multiple wins in categories Author of the Year and Female Vocalist of the Year. In 2012 and 2013, she was the art director of concert tour Męskie Granie.