Uncial 0309 (in the Gregory-Aland numbering), is a Greek uncial manuscript of the New Testament. Paleographically it had been assigned to the 6th-century.

The codex contains parts of six verses of the Gospels, on a fragment of one parchment leaf. Probably the original leaf was 18 cm by 13 cm. Only a small fragment 6 by 3 cm survives. Page verso is more legible. It contains the text of the Gospel of John 20:22-24,28-30.^[1][2]

It was written in one column per page, 27 lines per page, with only 6 lines surviving, in uncial letters.^[1]

Currently it is dated by the INTF to the 6th-century.^[1]

It is currently housed at the Institut für die Altertumskunde of the University of Cologne (Inv. 806) in Cologne.^[1]

• List of New Testament uncials
• Biblical manuscripts
• Textual criticism