Haredi Judaism consists of groups within Orthodox Judaism that are characterized by their strict interpretation of religious sources and their accepted halakha and traditions, in opposition to more accommodating or modern values and practices. Its members are usually referred to as ultra-Orthodox in English; however, the term "ultra-Orthodox" is considered pejorative by many of its adherents, who prefer terms like strictly Orthodox or Haredi. Haredi Jews regard themselves as the most religiously authentic group of Jews, although other movements of Judaism disagree.

Samson Raphael Hirsch was a German Orthodox rabbi best known as the intellectual founder of the Torah im Derech Eretz school of contemporary Orthodox Judaism. Occasionally termed neo-Orthodoxy, his philosophy, together with that of Azriel Hildesheimer, has had a considerable influence on the development of Orthodox Judaism.