Ottaviano Nelli (1375–1444) was an Italian painter of the early Quattrocento.
He was born in Gubbio, and active there and in Perugia (1400), Urbino, Assisi, and Foligno. Among his pupils was his brother Tommaso, Domenico Di Cecco di Baldi, Giovanni Pintali, Giacomo Di Bedo, and Ubaldo Di Matteo.
- Madonna del Belvedere (1403), Church of Santa Maria Nuova, Gubbio.
- Altar piece of Pietralunga (1404), Perugia, Galleria Nazionale dell'Umbria.
- Stories of Virgin Mary (1408 - 1413 circa), Frescoes, Church of San Francesco, Gubbio.
- Madonna del latte e angeli, Urbino, Oratorio dell'Umiltà.
- Stories of Virgin Mary (1424), Frescoes, Foligno, Chapel of Palazzo Trinci.
- Madonna del latte (post 1427), Urbino, Oratory of Santa Croce.
- Madonna della misericordia e santi, Urbino, Church of the Madonna dell'Homo
- Last Judgement, fresco, Church of Sant'Agostino, Gubbio.
- Madonna, fresco, Church of Santa Maria della Piaggiola, Gubbio