There are 3 15-letter words that end with 'ious'.
| hyperfastidious | excrementitious |
| ultrafastidious | |
Note: These 3 15-letter words that end with 'ious' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words end with cious, tious, rious, nious, dious, gious, vious, lious, mious, xious, bious, pious, hious, uious.
5-letter words end with 'ious' (1)