Azriel Hildesheimer (also Esriel and Israel, Yiddish: עזריאל הילדעסהיימער; 11 May 1820[1][2] – 12 June 1899) was a German rabbi and leader of Orthodox Judaism.

He attended the Hasharat Zvi school in Halberstadt, and, from age seventeen, the Yeshiva of Rabbi Jacob Ettlinger in Altona; chacham Isaac Bernays was one of his teachers and his model as a preacher.

In 1842 he went to Halle upon Saale where he earned his doctorate from the University of Halle-Wittenberg in 1844 under Wilhelm Gesenius and Emil Rödiger (Ueber die rechte Art der Bibelinterpretation, English: On the Right Kind of Bible Interpretation).

His first notable act there was to found a parochial school, where correct German was used, and modern principles of pedagogy were adopted in teaching secular, as well as Jewish, subjects.

Hildesheimer was "simple in his habits and fearless"; he had an unusual capacity for work; and his great Talmudic learning "was joined to practical administrative ability".

He was frequently engaged in philanthropic activities connected with his own congregation, but additionally, "no labor was too great and no journey too long for him" in the service of the Jews of Germany, Austria, Russia, and even Abyssinia and Persia, so that he came to be known as the "international schnorrer".

Other writings include: On the celebration of his seventieth birthday, in 1890, his friends and pupils published a literary Jubelschrift zum siebzigsten Geburtstag des Dr. Israel Hildesheimer, Rabbiner und Rector des Rabbiner-Seminars zu Berlin: Gewidmet von Freunden und Schülern / Hebrew: שי למורה: מאמרי תורה ודעת מחוברים לאות תודה ואהבה מובלים להרב עזריאל הילדעסהיימער... ביום מלאת לו שבעים שנה לימי חייו, יום כ״ז אייר שנת תר״ן (Berlin: H. Engel, 1890).

His firm conviction that traditional Judaism need have no fear of the light of European culture determined his attitude and his activity in Hungary and Germany from the start, and gave him a definite aim.

In an address delivered at his rabbinical seminary and defining his position he said: Unconditional agreement with the culture of the present day; harmony between Judaism and science; but also unconditional steadfastness in the faith and traditions of Judaism: these constitute the program of the New Community, the standard round which gather the Israelites of Berlin who are faithful to the Law.He thus undertook a variety of actions which render him a "modern" activist and institution-builder.

In the Hungarian Jewish Congress held at Budapest in 1869 he defined this party as representing a "faithful adherence to traditional teachings combined with an effective effort to keep in touch with the spirit of progress".