The Musar movement (also Mussar movement) is a Jewish ethical, educational and cultural movement that developed in the 19th century in Lithuania, particularly among Orthodox Lithuanian Jews. The Hebrew term Musar (מוּסַר), is from the book of Proverbs 1:2 meaning moral conduct, instruction or discipline. The term was used by the Musar movement to refer to efforts to further ethical and spiritual discipline. The Musar Movement made significant contributions to Musar literature and Jewish Ethics.
The Musar movement arose among the non-Hasidic Orthodox Lithuanian Jews as a response to the social changes brought about by the Enlightenment, and the corresponding Haskalah movement among many European Jews. In this period of history anti-Semitism, the assimilation of many Jews into Christianity, and the impoverished living conditions of many Jews in the Pale of Settlement caused severe tension and disappointment. Many of the institutions of Lithuanian Jewry were beginning to break up. Religious Jews feared that their way of life was slipping away from them, observance of traditional Jewish law and custom was on the decline, and even those who remained loyal to the tradition were losing their emotional connection to its inner meaning and ethical core.
The movement's founding is attributed to Rabbi Yisrael Lipkin Salanter (1810–1883), although the roots of the movements drew on ideas previously expressed in classical Musar literature. Prior to the founding of the Musar movement, musar was a practice of the solitary seeker; thanks to Salanter, it became the basis for a popular social/spiritual movement.