Papyrus 21 (in the Gregory-Aland numbering), designated by siglum ðÂÂÂ<sup>21</sup>, is an early copy of the New Testament in Greek. It is a papyrus manuscript of the Gospel of Matthew, it contains only . The manuscript paleographically had been assigned to the early 4th century.
The manuscript is written in large upright uncial letters.
The Greek text of this codex probably is a mixture of text-types. Aland placed it in Category III.
In it has textual variant ùôÃÂý ôõ (instead of õùôÃÂàôõ) in agreement with Codex Bezae, corrector b of the Codex Sinaiticus, 892*, the Latin text of Codex Bezae (it<sup>d</sup>), k, c, s, cop<sup>bo</sup>. In it lacks words ñàÃÂàÿàÃÂõ.
It is currently housed at the Muhlenberg College (Theol. Pap. 3) in Allentown (Pennsylvania).