Messianic Judaism (Hebrew: יַהֲדוּת מְשִׁיחִית‎ or יהדות משיחית, Yahadút Mešiḥít) is a modernist and syncretic movement of Protestant Christianity that incorporates some elements of Judaism and other Jewish traditions into evangelicalism.

It emerged in the 1960s and 1970s from the earlier Hebrew Christian movement, and was most prominently propelled through the non-profit organization "Jews for Jesus" founded in 1973 by Martin "Moishe" Rosen, an American minister under the Conservative Baptist Association.

Evangelical Protestants who identify as Messianic Jews believe that Jesus (referred to by the Hebrew-language name Yeshua among adherents) is the Jewish Messiah prophesied in the Hebrew Bible, and that the Hebrew Bible (or Old Testament) and the New Testament are the authoritative scriptures of mankind. Salvation in Messianic Judaism is achieved only through the acceptance of Jesus as one's saviour, and not through adherence to Jewish rabbinical law. Belief in Jesus as a messianic figure and as divine (i.e. God the Son) is considered by Jews to be one of the most defining distinctions between Judaism and Christianity.

Among other evangelical groups, Messianic Judaism is usually accepted as a form of Christianity. However, adherents of Messianic Judaism claim that the movement is instead a form of Judaism. In the Hebrew language, they tend to identify themselves with the terms maaminim (מאמינים, lit. 'believers') and yehudim (יְהוּדִים‬‎‎, lit. 'Jews') in opposition to being identified as notzrim (נוצרים, lit. 'Christians'). Jewish organizations inside and outside of Israel reject this framing; the Supreme Court of Israel has also rejected this claim in cases related to the Israeli Law of Return, and Messianic Judaism is recognized only as a Christian movement in the country. In this context, there is discourse among scholars as to whether Messianic Judaism should be labeled a Jewish or Christian religious sect.

From 2003 to 2007, the movement grew from 150 Messianic houses of worship in the United States to as many as 438, with over 100 in Israel and more worldwide; congregations are often affiliated with larger Messianic organizations or alliances. As of 2012, Messianic population estimates were between 175,000 and 250,000 members in the United States, between 10,000 and 20,000 members in Israel, and an estimated total worldwide membership of 350,000.