Rabbi Menachem Mendel Hager of Kosov (Hebrew: מנחם מנדל הגר), nicknamed the "Ahavat Shalom", (1768–29 October 1825) was a Hasidic rebbe and founder of the Kosov dynasty, which he led from 1802 until his death in 1825.

From an early age, he devoted most of his life to Torah study and only engaged in commerce enough to earn a living for basic necessities.

He accepted the position of rabbinate in Kosov and became the mentor to thousands of Hasidim.

[4] Becoming popular among Hasidim, Rabbi Simcha Bunim of Peshischa said that his feet burned to want to meet the rebbe of Kosov.

[3] After the death of his wife, Rabbi Moshe Leib of Sasov sent two children, a boy and a girl, to Hager, his former student, to take care of their upbringing and education.