Irena Stanisława Sendler, also referred to as Irena Sendlerowa in Poland, nom de guerre Jolanta, was a Polish humanitarian, social worker, and nurse who served in the Polish Underground Resistance during World War II in German-occupied Warsaw. From October 1943 she was head of the children's section of Żegota, the Polish Council to Aid Jews.
In the 1930s, Sendler conducted her social work as one of the activists connected to the Free Polish University. From 1935 to October 1943, she worked for the Department of Social Welfare and Public Health of the City of Warsaw. During the war she pursued conspiratorial activities, such as rescuing Jews, primarily as part of the network of workers and volunteers from that department, mostly women. Sendler participated, with dozens of others, in smuggling Jewish children out of the Warsaw Ghetto and then providing them with false identity documents and shelter with willing Polish families or in orphanages and other care facilities, including Catholic nun convents, saving those children from the Holocaust.