Is it normal to sleep with your mouth open?
Mostly.Normal for most people
Yes, it’s fairly common to sleep with your mouth open, especially if your nose is stuffy or you naturally breathe through your mouth. By itself, it usually isn’t a big deal.
A blocked nose from allergies, a cold, or dry air can make mouth-breathing more likely, and some people simply do it while they’re asleep. You might wake up with a dry mouth or throat, which is annoying but common.
If it happens often along with loud snoring, gasping, breathing pauses, or feeling unusually tired during the day, it’s worth mentioning to a healthcare professional, since those symptoms can point to a sleep or breathing problem.