Codex 0308 (in the Gregory-Aland numbering), is one of the recently registered New Testament Greek uncial manuscripts.

It consists of only a fragment of a single parchment leaf of a fourth-century codex, containing portions of the eleventh chapter of the Book of Revelation.

The letters Ε (epsilon) and Θ (theta) have an extended middle line, and they are similar to those from Codex Washingtonianus.

The nomina sacra attested in this uncial fragment are ΚΣ (Kurios, Lord) and ΧΡΣ) (Christos, Christ).

In Rev 11:16 it has the textual variant κα]θημενο[ι, agreeing with Codex Alexandrinus, Uncial 051 and