In this thesis, I explore the differences between proto-orthodox and gnostic proselytization beliefs and practices as expressed in their respective texts during the era of doctrinal conflict before the Council of Nicaea in 325 CE in an attempt to explain why these differences existed and how proto-orthodox Christian leaders saw their sect’s emphasis of proselytization as an important distinction between themselves and their gnostic counterparts. Proto-orthodox texts reveal a strong belief in global proselytization, and proto-orthodox leaders stressed that evangelism was a divine command from God that contemporary Christians were supposed to obey. However, gnostic religious texts, commentaries, and letters do not place nearly as much emphasis on proselytization and do not see proselytization as a command from God or something that gnostic believers should practice. Rather, gnostic texts reveal that gnostic believers should focus on internal revelation and special knowledge. While gnostic Christians clearly shared their faith with others, the doctrinal importance of proselytization differed from that of the proselytization focused proto-orthodox Christians. These varying beliefs on evangelism and its relative importance demonstrate a contrast in proselytization beliefs as it relates to the doctrinal discussion between proto-orthodox and gnostic believers in the first 4 centuries CE that has not been comprehensively examined by academia. While some of the practicalities of proto-orthodox proselytization were likely similar in some respects to gnostic proselytization practices, such as not sharing complicated doctrine at once, proto-orthodox Christian leaders argued that the differences in proselytization were doctrinally significant and was a point of contention between these two sects.