Messianic Jews assert that one can be Jewish and also believe in Jesus Christ. They claim a continuous tradition originating with the disciples of Jesus, who were all practicing Jews and believers. However, a survey of the development of Messianic Judaism shows that there is no continuous tradition. Messianic Judaism is more accurately considered the result of social forces such as Protestant missions to the Jews, the counterculture movement, and the resurgence of Jewish ethnic identity after the 1967 war. In mixing Jewish heritage and Christian belief, Messianic Jews obscure the Jewish/Christian boundary. This thesis analyses the construction of culture within the framework of that boundary. Field methods were employed to gain insight into two Messianic communities. In considering these groups, particular attention is given to the roles of history and ritual in the mediation of ethnic boundaries and the shaping of a viable Messianic Jewish identity.