There are 161 15-letter words that end with 'ing'.
Note: These 161 15-letter words that end with 'ing' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words end with ting, ling, ring, ning, sing, zing, ding, king, ying, hing, ging, ping, ming, cing, wing, ving, bing, fing, eing, oing, uing, xing, aing, iing.
4-letter words end with 'ing' (9)