Or at least...we think it is?
If Ellen DeGeneres tweets about it, then it must be true. Right?
National Punctuation Day doesn't appear to have a Twitter profile, but there is a Facebook page.
Well, as a writer, I try to recognize National Punctuation Day every day. That means the holiday is a break from using it, right?— D.J. Tatsujin (@djtatsujin) September 24, 2016
That didn't stop Twitter users from having some fun, though.
To help the uninformed, TIME has an online punctuation quiz.