The relations between Gregory IX and Judaism were comparatively good for a medieval pope,^{[citation needed]} since Gregory acted as a political protector to persecuted Jewish communities. However, he also enacted canonical laws that were later criticized for having maintained the Jews' separate status in medieval society.

• 6 April 1233 "Mandate, if facts are established, to the archbishops and bishops of France to induce the Christians in their dioceses to stop persecuting the Jews, who had complained to the pope that they were being maltreated and tortured by certain lords, imprisoned and left to die. The Jews are willing to forsake usury. They are to be set free and are not to be injured in person or in property."

In the 1234 Decretals, he invested the doctrine of perpetua servitus iudaeorum – perpetual servitude of the Jews – with the force of canonical law. According to this, Jews would have to remain in a condition of political servitude and abject humiliation until Judgment Day. The doctrine then found its way into the doctrine of servitus camerae imperialis, or servitude immediately subject to the Emperor's authority, promulgated by Frederick II.

The second-class status of Jews thereby established would last until well into the 19th century.^[1]

• 3 May 1235 "Protection provided to Jews by standard formula of Sicut Judeis."