There are 10 13-letter words that end with 'tting'.
| hairsplitting | globetrotting | 
| interknitting | interknotting | 
| photostatting | sidesplitting | 
| preformatting | pretermitting | 
| summersetting | thermosetting | 
Note: These 10 13-letter words that end with 'tting' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words end with etting, itting, otting, atting, utting.
7-letter words end with 'tting' (45)