Apollos was an early Christian, who is mentioned several times in the New Testament. His special gifts in presenting Christian doctrine made him an important person in the congregation at Corinth, Greece, and his name came to be attached to a faction there (1 Corinthians 1:12), but there is no indication that he favored or approved an overestimation of his person. Paul considered Apollos to be a valuable helper in carrying on his work in the important Corinthian congregation (1 Cor. 3:6, 4:6, 16:12).
In harmony with Paul's notices are the statements of the Acts of the Apostles (18:24-28) that Apollos was a highly educated Alexandrian Jew, who came to Ephesus (probably in 54), was instructed in the gospel there by Aquila and Priscilla, and afterwards settled in Achaia, where he showed himself useful to the Church.
It is difficult to get a correct idea of his religious standpoint; but it probably was that of the so-called disciples of John the Baptist (Acts 19:1-7). Taken all in all, it may be said that Apollos was a zealous missionary, who, while confessing Jesus, did not have the full New Testament revelation, and stood in danger of becoming antagonistic to the apostolic message to all the world; he became, however, an adherent of the Pauline doctrine, and the author of the Acts of the Apostles thought this fact of sufficient importance to be included in his history. In the Epistle to Titus (3:13) Apollos is mentioned, with Zenas , as bearer of the letter to Crete.
The Epistle to the Hebrews has often been ascribed to Apollos, beginning with Martin Luther.
Initial text from Schaff-Herzog Encyclopedia of Religion