Rosh yeshiva (Hebrew: ראש ישיבה; pl. Heb. rashei yeshiva; pl. Yeshivish: rosh yeshivahs) is the title given to the dean of a Talmudical academy (yeshiva). It is a compound word of the Hebrew words rosh ("head") and yeshiva (a school of religious Jewish education). The rosh yeshiva is required to have a comprehensive knowledge of the Talmud and the ability to analyse and present new perspectives, called chidushim () verbally and often in print.
The primary role of the rosh yeshiva is not simply to be the dean, but is generally to say the highest-level lecture in the yeshiva, which is usually a program of at least two years. Students who have studied in a yeshiva are generally known as "students of the rosh yeshiva", as his lecture is the one in which they usually attain their method of Talmudic analysis and critical reasoning, and this method is based on the particular style of that rosh yeshiva. In addition, since yeshivas play a central role in the life of certain communities within Orthodox Judaism, the position of rosh yeshiva is more than just his position within the yeshiva. A rosh yeshiva is often seen as a pillar of leadership in extended communities. In Hasidic Judaism, the role of rosh yeshiva is secondary to the rebbe, who is head of the Hasidic dynasty that controls it. In many Hassidic sects, the rosh yeshiva of a school will be the son or son-in-law of the rebbe, the assumed heir of the rebbe. However, the role that yeshivohs have within Hasidic communities is not nearly as important as it is in Lithuanian Jewish (Litvishe) communities. Hassidic students usually get married at the age of 18, which – in most cases – is the end of their yeshiva education, while students in the Lithuanian Jewish communities continue to study, at a minimum till they get married starting at age 23, and the vast majority continue their studies after marriage. As a result, the role that a rosh yeshiva plays in Lithuanian Jewish communities is much more important than in the Hassidic ones.