De regimine Judaeorum, ad Ducissam Brabantiae

De regimine Judaeorum, ad Ducissam Brabantiae (lit. 'On the government of the jews, to the Duchess of Brabant'), also known as the Epistula ad Ducissam Brabantiae, is an epistle written by Dominican friar and Catholic saint Thomas Aquinas to Adelaide of Burgundy, Duchess of Brabant.

Despite its briefness, De regimine Judaeorum soon became one of the most widely quoted short works by Aquinas and has been characterized as a relevant document to understand the doctor's personal opinions on Judaism, as it deviates from the rather systematic approach used in the Summa Theologiae.^[1]