There are 9 15-letter words that start with 'ag'.
| agglutinability | aggrandizements |
| aggregatenesses | agranulocytoses |
| agranulocytosis | agreeablenesses |
| agribusinessman | agribusinessmen |
| agriculturalist | |
Note: These 9 15-letter words that start with 'ag' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with agg, agr, age, aga, ago, agi, agn, agl, agu, agh, agm, ags.
3-letter words start with 'ag' (4)