Theodor Innitzer (25 December 1875 – 9 October 1955) was Archbishop of Vienna and a cardinal of the Catholic Church.

Despite his initial support for the Nazi party, his home later became a refuge for Jews, while he strove to alleviate public misery and restore the Austrian Church, disassociating himself from politics.

Innitzer was born in Neugeschrei (Nové Zvolání), part of the town Weipert (Vejprty) in Bohemia, at that time Austria-Hungary, (now Czech Republic). He was the son of a passementier Wilhelm Innitzer in Vejprty, later a textile factory worker, and his wife Maria born Seidl, daughter of a mining clerk. After completing the minimum mandatory school, Innitzer became an apprentice in a textile factory. The dean of his home parish supported young Theodor, thus paving the way for him to attend higher schools (Gymnasium) in Kaaden.

Innitzer's role in early 20th century Austrian history remains disputed because of his involvement in politics. Despite early support for the Anschluss, Innitzer became a critic of National Socialism and was subject to further violent intimidation.

This assessment stems from his cooperation with the Austro-fascist government of Engelbert Dollfuß and Kurt Schuschnigg from 1934 to 1938, which based many of its economic and social policies on the teachings of the Catholic Church. He and the other Austrian Catholic bishops signed a declaration endorsing the Anschluss, set up by Gauleiter Josef Bürckel, and signed by Innitzer with "Heil Hitler!". Without the bishops' consent, the Nazi regime disseminated this statement throughout the German Reich.

Vatican Radio had recently broadcast a vehement denunciation of the Nazi action, and Cardinal Pacelli (soon to become Pope Pius XII) ordered Innitzer to report to the Vatican. Before meeting with Pius XI, Innitzer met with Pacelli, who had been outraged by Innitzer's statement. He made it clear that Innitzer needed to retract and was made to sign a new statement, issued on behalf of all the Austrian bishops, which asserted that "the solemn declaration of the Austrian bishops ... was clearly not intended to be an approval of something that was not and is not compatible with God's law." The Vatican newspaper also reported that the bishops' earlier statement had been issued without the approval of the Holy See.

In April 1938, in honour of Hitler's birthday, Cardinal Innitzer had ordered that all Austrian churches fly the swastika flag, ring bells, and pray for Hitler. Innitzer also called a day of prayer in the Cathedral of St. Stephen of Vienna for 7 October 1938, which was attended by almost 9,000 people, mostly young people. In the sermon, Innitzer declared that "we must confess our faith in our Führer, for there is just one Führer: Jesus Christ." Nazi leaders were angered: about 100 Nazis, among them many older members of the Hitler Youth, ransacked the archbishop's residence the next day. In Britain, the Catholic Herald provided the following contemporary account on 14 October 1938:

The invasion was a reply to a courageous sermon the Cardinal had preached in the Cathedral earlier in the evening, in which the Cardinal told his packed congregation that "in the last few months, you have lost everything!' This sermon marked the end of Cardinal Innitzer's attempt to establish a religious peace with the Nazis. The attempt has failed. Cardinal Innitzer is now in line with his German brothers, openly urging Catholics to resist anti-Catholic measures. [...] Nazi mobs have penetrated into the Archbishop's Palace on St. Stephen's Square in Vienna and have demolished part of the furniture. Other furniture, as well as files and documents were thrown through the windows and set on fire. Hostile cries like "down with the clergy," "send the Cardinal into a concentration camp," "traitor bishop" and so on were heard.