There are 21 6-letter words that start with 'op'.
| opaque | opened | opener | openly | operas |
| operon | ophite | opiate | opined | opines |
| opioid | opiums | oppose | oppugn | opsins |
| optics | optima | optime | opting | option |
| opuses | ||||
Note: These 21 6-letter words that start with 'op' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with ope, opp, opt, opa, opi, oph, opu, ops, opo.
3-letter words start with 'op' (3)