Celio (Italian: [ˈtʃɛːljo]) is the 19th rione of Rome, Italy, identified by the initials R. XIX, and is located within the Municipio I.

Up to 1870, the area was moderately inhabited, with some major religious building and many archaeological remains appearing in the vast filed and vineyards.

Up until the postwar period, the road scheme has been reworked in the lower part of the rione, near the Colosseo, and in 1968 a big public housing complex, that was located among Piazza Celimontana, Via Claudia, Via Annia and Via dei Simmachi, was demolished: the plot, facing the military hospital, is now a public park (Parco della Pace).

It is moderately inhabited and scarcely congested, and can be considered a working-class borough, if compared with more central rioni.

Westward, Celio shares a short border with Ripa (R. XII), marked by Piazza di Porta Capena.