Jan Polák ( [ˈjan ˈpolaːk]; born 14 March 1981) is a Czech international footballer who plays as a midfielder for FC Zbrojovka Brno in the Czech First League.
In his younger days he played for FC Zbrojovka Brno and Tatran Bohunice. Formerly a member of the Czech national under-21 side, Polák, alongside players like Petr Čech and Milan Baroš, was a part of the team which won the European Under-21 Football Championship in 2002. He also holds the record for the most appearances for the Czech Republic under-21 team.
In 2005, he was transferred from the Czech Premier League team FC Slovan Liberec for a fee of €1,500,000 to the Bundesliga side 1. FC Nürnberg. In the same year he played for the first time under Czech national coach Karel Brückner.
On 3 August 2007, Anderlecht bought Polák. He was given number 8. The Czech international reportedly cost €3.5 million and is the second most expensive transfer in Anderlecht's history, as well as one of the highest paid players in Belgian football. He was Anderlecht's box-to-box midfielder playing a crucial role in their 2007–08 Jupiler League season and the 2007–08 UEFA Cup.