Universal Pictures celebrated the theatrical release of THE GRINCH by partnering with Honda during its annual Honda Holiday campaign. The promotion featured a takeover of Honda's Twitter account by THE GRINCH himself, who hacked the account at 9 am on Nov. 19, 2018 and started sharing his signature unhappy and un-merry comments. The character also appeared on Honda's Instagram, Facebook, Snapchat and YouTube channels to spread the word about the Twitter takeover.

Honda aired a TV spot during Sunday football games showing the animated character taking over a Honda dealership and announcing the arrival of "UnHappy Honda Days." Another TV Spot was aired shortly after in which The Grinch had a change of heart and returned everything he had stolen. The campaign continued with segments on NBC’s "Today" show on Nov. 20 and E!’s Snapchat show, "The Rundown," on Nov. 19 and Nov. 21.