The Nazarenes (or Nazoreans; Greek: Ναζωραῖοι, Nazōraioi) were an early Jewish Christian sect in first-century Judaism. The first use of the term is found in the Acts of the Apostles (Acts 24:5) of the New Testament, where Paul the Apostle is accused of being a ringleader of the sect of the Nazarenes ("πρωτοστάτην τε τῆς τῶν Ναζωραίων αἱρέσεως") before the Roman procurator Antonius Felix at Caesarea Maritima by Tertullus. At that time, the term simply designated followers of Jesus of Nazareth, as the Hebrew term נוֹצְרִי‎ (nôṣrî), and the Arabic term نَصْرَانِي (naṣrānī), still do.

As time passed, the term came to refer to a sect of Jewish Christians who continued to observe the Torah along with Noachide gentiles who were grafted into the covenant, in contrast to gentile Christians who eschewed Torah observance. They are described by Epiphanius of Salamis and are mentioned later by Jerome and Augustine of Hippo. The writers made a distinction between the Nazarenes of their time and the "Nazarenes" mentioned in Acts 24:5.