We Wish You a Merry Christmas - Super Simple Channel (has to be this specific version)
YouTube Link:
https://www.youtube.com/watch?v=hNkvV4PR-q0
My students are maybe on the average side, most probably not advanced, and I dunno about you, but the other Christmas songs are either too difficult for ESL learners (even Jingle Bells' verses seem too hard) or the concepts/theme of the lyrics are weird or inappropriate for ES kids.
So I chose We Wish You a Merry Christmas. It's repetitive (the chorus and verses are repeated 3x each), and it includes a common holiday greeting which they can be exposed to already (Merry Christmas, Happy New Year).
This specific version also includes 4 actions, so that even if kids can't sing the verses, they can follow along with the actions. Makes it more energetic and fun too!
For the kids who do want to learn the rest of the lyrics, the verses in this one are quite easy enough, and repetitive too. (...Christmas is here!)
The 2nd verse might be tricky (Happy Holidays to you...), so we asked kids to just sway or do other dance moves.
Make sure to exaggerate the difference between whispering (chisana koe) and the last verse - big voices (ookiina koe). This adds variation to the song too.
Enjoy!