Tadeusz Iwiński (pronounced [taˈdɛ.uʂ iˈvij̃skʲi]; born 28 October 1944) is a Polish politician. He was from 1991 to 2015 a member of the Sejm (the lower house of the Polish parliament), elected to represent the Olsztyn electoral district from the list presented by the Democratic Left Alliance (Sojusz Lewicy Demokratycznej). He had earlier (1967–1990) been a long-serving member of the communist Polish United Workers Party (Polska Zjednoczona Partia Robotnicza).