Tadeusz Reytan (or Tadeusz Rejtan, rarely Reyten; 20 August 1742 – 8 August 1780) was a nobleman from the Polish–Lithuanian Commonwealth.
He was a member of the Polish Sejm from the constituency of Nowogródek.
Rejtan is remembered for a dramatic gesture he made in September 1773, as a deputy of the Partition Sejm.
There, Rejtan tried to prevent the legalization of the first partition of Poland, a scene that has been immortalized in the painting Rejtan by Jan Matejko.
He has been the subject of many other art works, and is a symbol of patriotism in Belarus and Poland.
Despite his efforts, the partition of Polish–Lithuanian Commonwealth was legalized soon afterwards.