Yahudanci masu ra'ayin mazan jiya ƙungiya ce ta Yahudanci da ke neman kiyaye al'adar Yahudawa yayin da kuma ke ba da izinin wasu sabuntawa da daidaitawa zuwa yanayin zamantakewa da al'adu na zamani. Yana jaddada mahimmancin doka da al'adar Yahudawa, yayin da kuma sanin buƙatar mayar da martani ga canje-canjen yanayi da ra'ayoyi. Yahudanci mai ra'ayin mazan jiya ya fito a ƙarshen 19th da farkon ƙarni na 20 don mayar da martani ga ra'ayin wuce gona da iri na Reform Yahudanci, wanda ya ƙi yawancin al'adun Yahudawa da imani da yawa, da Yahudanci Orthodox, waɗanda suka ƙi zamani. Addinin Yahudanci masu ra'ayin mazan jiya shine darika na biyu mafi girma na Yahudanci a Arewacin Amurka, bayan Reform Yahudanci, kuma yana nan a wasu sassan duniya.