Agata Danuta Mróz-Olszewska (born April 7th 1982 in Dąbrowa Tarnowska, died June 4th 2008 in Wrocław) – Polish volleyball player. 138 matches in the national team (2003−2006), two-time gold medallist of the European Championship (2003 and 2005).

Her talent was noticed when she was a young girl. That is why she was offered a place in the School of Sports Championship in Sosnowiec, run by the Polish Volleyball Federation. In the third year of its general secondary school, she achieved her first important success. The Polish Cadet national team, with Agata Mróz as captain, won a gold medal of the European Cadet Championship in Gdańsk. Soon after that, in the spring of 2000, she stopped training due to first symptoms of her disease. She completed the third year of the School of Sports Championship’s secondary school and returned to Tarnów.

After a long break, she started to train with an academic team from Ostrowiec Świętokrzyski, playing in B-series of women’s volleyball league. Then she was first called up to the national team. The decision caused quite a stir as Agata Mróz, despite her junior achievements, was rather an unknown player. Her club, AZS WSBiP Ostrowiec Świętokrzyski, was not well-known either. Nonetheless, she turned out to be one of the crucial players of the national team, in which she won a gold medal of the European Championship (2003). As a result, numerous leading clubs, not only from Poland, got interested in this previously unknown player. Agata Mróz decided to play in BKS Bielsko-Biała, in which she won the Championship of Poland (2004) and two Polish Cups (2004 and 2006).

She played for the national team many times. In 2005 she again won a gold medal of the European Championship. From 2006 she played in Gruppo Murcia 2002, a Spanish team, in which she won the Champioship and the Cup of Spain (2007). In 2007 she ended her career due to ill health.