There are 12 words that start with 'koo'.
| kook | kooks | kooky |
| koodoo | kookie | koodoos |
| kookier | kookiest | kookiness |
| kookaburra | kookaburras | kookinesses |
Note: These 12 words that start with 'koo' are found from the USA & Canada version of the tournament Scrabble word list.