Pope Linus (/ˈlaɪnəs/ ^ⓘ; Greek: Λῖνος, Linos; died c. 80) was the bishop of Rome from c. 68 to his death in 80. He is generally regarded as the second bishop of Rome, after Saint Peter. As with all the early popes, he was canonized.

According to Irenaeus, Linus is the same person as the one mentioned in the New Testament. Linus is mentioned in the valediction of the Second Epistle to Timothy (2 Timothy 4:21) as being with Paul the Apostle in Rome near the end of Paul's life.

The earliest reference to the episcopate of Linus was Irenaeus, who in c. 180 wrote that "the blessed apostles, then, having founded and built up the Church, committed into the hands of Linus the office of the episcopate".

According to the earliest succession lists of bishops of Rome, passed down by Irenaeus and Hegesippus and attested by the historian Eusebius, Linus was entrusted with his office by the apostles Peter and Paul after they had established the Christian church in Rome. By this reckoning he might be considered therefore the first pope, but from the late 2nd or early 3rd century the convention began of regarding Peter as the first pope.

Jerome described Linus as "the first after Peter to be in charge of the Roman Church" and Eusebius described him as "the first to receive the episcopate of the church at Rome, after the martyrdom of Paul and Peter". John Chrysostom wrote that "this Linus, some say, was second bishop of the Church of Rome after Peter", while the Liberian Catalogue described Peter as the first bishop of Rome and Linus as his successor in the same office.

The Liber Pontificalis also enumerated Linus as the second bishop of Rome after Peter, and stated that Peter consecrated two bishops, Linus and Anacletus, for the priestly service of the community, while devoting himself instead to prayer and preaching, and that it was Clement I to whom he entrusted the universal Church and whom he appointed as his successor. Tertullian also wrote of Clement as the successor of Peter. Jerome named Clement as "the fourth bishop of Rome after Peter, if indeed the second was Linus and the third Anacletus, although most of the Latins think that Clement was second after the apostle".

The Apostolic Constitutions note that Linus, whom Paul the Apostle consecrated, was the first bishop of Rome and that he was succeeded by Clement I, whom Peter the Apostle ordained and consecrated.

The chronology of the early popes is heavily disputed. Eusebius and Jerome dated Linus' episcopate between the years 68 and 80. The Liberian Catalogue and the Liber Pontificalis date it as 56 to 67, during the reign of Nero. This is most likely a mistake, as all four sources give Peter an episcopate of 25 years in Rome, and the Liber Pontificalis even records that Peter died 38 years after Jesus' death, that is, 67–68. The Catholic Encyclopedia gives his years as c. 64–76 or c. 67–79.