Znak (Polish: Sign, Symbol) was an association of lay Catholics in Poland, active between 1956 and 1976. It was the only Catholic organisation that was tolerated by the communist Polish United Workers' Party and supported the Catholic hierarchy.
It was created as one of several smaller groups that sprung up after dissolution of the communist-controlled association PAX of Bolesław Piasecki in 1956. It was granted with several seats in the Polish Sejm and was intended as a link between the Catholic Church and the state. As such it was allowed to cooperate with various Western European catholic movements, among them the German section of the International Catholic Peace Movement Pax Christi.
- Tadeusz Mazowiecki
- Jerzy Zawieyski
- Stefan Kisielewski
- Stanisław Stomma
- Wanda Pieniężna
- Janusz Zabłocki
During the March 1968 anti-Semitic and anti-intelligentsia campaign of Władysław Gomułka, Znak was the only political organisation in Sejm to protest against it. In 1976 member of Znak, Stanisław Stomma, the single Znak member of the Sejm, was, through abstaining from voting, one of only two Members of Parliament not to approve the amendment of Polish constitution underlining the "leading role" of the communist party and the "eternal friendship" with the USSR. As a reprisal the Znak was disbanded.
A remainder of the group existed until 1980 when it was renamed to Polski Związek Katolicko-Społeczny, which like the Znak had representatives in the Sejm and continues today as a Catholic charity organisation. It was notable for its opposition to martial law in Poland.