Gerontius (/dʒɪˈrɒntiəs, ɡɪˈrɒntiəs/; Latinized Greek for 'old man') can refer to:
Music and literature
- The Dream of Gerontius, a 1900 choral work by Edward Elgar, a setting of a poem of the same name by John Henry Newman
- The Dream of Gerontius, the poem by John Henry Newman
People
- Gerontius (bishop of Milan), bishop of Milan (462-465)
- Gerontius of Cervia, 6th-century Italian bishop
- Gerontius, Metropolitan of Moscow, 1473-1489
- Gerontius (magister militum), early 5th-century Roman general
- Gerontius (commander), early 4th-century Roman commander of Tomis
Fiction
- Gerontius, a 1989 novel by James Hamilton-Paterson
- Gerontius, the given name of the Old Took, a hobbit mentioned in J. R. R. Tolkien's fantasy series The Lord of the Rings