Why Does My Child Sleep With Their Mouth Open? What Parents Should Know
Estimated Reading Time: 8–10 minutes
You check on your child before heading to bed and notice something you've probably seen dozens of times before.
They're sound asleep—but their mouth is hanging open.
Maybe they snore a little. Maybe their pillow is damp in the morning. Maybe they wake up thirsty, toss and turn all night, or somehow end up sideways in the bed.
It's easy to assume that's simply how they sleep.
But persistent open-mouth sleeping can be a clue worth paying attention to.
As a Myofunctional Therapist, one of the most important things I want parents to understand is that we shouldn't start by asking:
"How do I get my child to keep their mouth closed?"
A better question is:
"Why does my child need to open their mouth to breathe?"
And that question can lead us somewhere much more useful.
Mouth Breathing Isn't Always Just a Habit
Children aren't usually lying in bed consciously deciding whether they'll breathe through their nose or mouth.
Their body is trying to breathe.
If breathing comfortably through the nose is difficult, the mouth provides another pathway for air.
There can be many reasons a child regularly breathes through their mouth, including nasal congestion, allergies, enlarged tonsils or adenoids, structural differences, or other airway concerns.
Sometimes the original obstacle improves, but the breathing pattern remains.
That's when function and habit may also become part of the picture.
This distinction matters because repeatedly telling a child to "close your mouth" doesn't address the reason their mouth is open.
If nasal breathing isn't comfortable or possible, we need to understand why before trying to retrain anything.
Signs That Can Accompany Open-Mouth Sleeping
Mouth breathing at night may not be the only thing you notice.
Parents sometimes describe:
Snoring or noisy breathing
Restless or disrupted sleep
Frequent waking
Drooling on the pillow
Dry mouth or cracked lips in the morning
Mouth breathing during the daytime
Difficulty comfortably keeping the lips together
A tongue that appears to rest low in the mouth
Teeth grinding
Unusual sleeping positions
Waking tired despite spending enough time in bed
Irritability or difficulty concentrating during the day
None of these signs by itself tells us exactly what is happening.
And noticing them does not automatically mean your child has a sleep or airway disorder.
Think of them as pieces of information.
When several occur consistently, they're worth discussing with an appropriate healthcare professional rather than simply assuming your child is a "mouth breather."
Why Does Nasal Breathing Matter?
Your nose isn't simply an alternative entrance for air.
It is designed for breathing.
Nasal breathing helps filter, warm, and humidify the air before it travels farther into the respiratory system.
But there's another reason nasal breathing matters in the world of Myofunctional Therapy:
Breathing and oral resting posture are connected.
Try comfortably resting your tongue against the roof of your mouth while intentionally breathing through your mouth.
Not very easy, right?
When the mouth needs to remain open for breathing, the lips and tongue often have to adapt.
And when that pattern happens hour after hour, day after day, it can influence the way the muscles of the mouth and face learn to rest and function.
Where Should the Tongue Rest?
When we're not eating or talking, our tongue still has a job.
Generally, the tongue should be able to rest comfortably against the roof of the mouth, with the lips relaxed and together and breathing occurring through the nose when the airway allows.
A child who frequently breathes through their mouth may instead develop an open-mouth posture with the tongue resting lower.
Over time, that can become the body's familiar resting pattern.
That's one reason I look at much more than simply whether someone can stick their tongue out.
During a Myofunctional evaluation, we're interested in how the entire system functions together—breathing, tongue posture, lip function, swallowing, oral habits, and muscle coordination.
Face Value's approach is specifically built around evaluating those patterns and developing individualized, habit-focused therapy when appropriate.
Can Mouth Breathing Affect Sleep?
Breathing and sleep are closely connected, but this is an area where it's especially important not to jump to conclusions.
A child who sleeps with their mouth open does not automatically have a sleep disorder.
At the same time, persistent mouth breathing—particularly when it occurs alongside frequent snoring, noisy breathing, restless sleep, or daytime symptoms—deserves attention.
One of the biggest mistakes we can make is normalizing a pattern simply because we've seen it for a long time.
Common doesn't always mean something should be ignored.
If you're concerned about your child's breathing or sleep, their pediatrician or another qualified healthcare professional is an appropriate place to begin.
Where Does Myofunctional Therapy Fit?
This is where I want to make an important distinction.
Myofunctional Therapy doesn't remove enlarged tonsils.
It doesn't diagnose allergies.
It doesn't correct a structural nasal obstruction.
And it shouldn't be used to force a child to breathe through their nose when something is making nasal breathing difficult.
Those issues may require evaluation and treatment from other healthcare professionals.
Myofunctional Therapy addresses the functional side of the equation.
Once nasal breathing is appropriate and comfortable, therapy may focus on patterns such as:
Nasal breathing awareness and habit development
Appropriate oral resting posture
Tongue position
Comfortable lip closure
Swallowing patterns
Oral and facial muscle coordination
Replacing long-standing dysfunctional habits with healthier ones
That's why collaborative care is such an important part of Face Value's philosophy. Depending on the child, dentists, orthodontists, ENTs, pediatricians, sleep professionals, allergists, and other providers may all have different pieces of useful information.
Great care doesn't mean making one provider the answer to everything. It means figuring out which pieces of the puzzle matter for that particular child.
What Should Parents Do First?
You don't need to diagnose anything yourself.
Instead, become a good observer.
For a week or two, notice:
During sleep
Is your child's mouth usually open?
Do they snore?
Is their breathing noisy?
Do they toss and turn frequently?
Do they wake during the night?
In the morning
Is their mouth unusually dry?
Are their lips cracked?
Do they complain of being tired?
Do they seem well rested?
During the day
Is their mouth frequently open at rest?
Do they breathe through their mouth while watching TV or using a tablet?
Where does their tongue seem to rest?
Do they struggle to comfortably maintain closed lips?
Have you noticed unusual swallowing patterns or other oral habits?
You don't need to check every box.
You're simply looking for patterns.
Those observations can make conversations with your child's healthcare providers much more productive.
What Happens During a Myofunctional Evaluation?
If oral function appears to be part of the picture, an evaluation allows us to look more closely at the patterns involved.
At Face Value, that may include evaluating areas such as breathing, oral resting posture, tongue function and mobility, lip function, swallowing, oral habits, and muscle coordination.
From there, we can determine whether Myofunctional Therapy may be appropriate—or whether another provider should be involved first.
Sometimes the most valuable outcome of an evaluation isn't immediately beginning therapy.
Sometimes it's figuring out which question needs to be answered next.
The Takeaway for Parents
If your child occasionally sleeps with their mouth open because they have a cold, that's very different from seeing the same pattern night after night.
Persistent mouth breathing is something to understand, not something to panic about.
And it's not something we solve by simply reminding a child to close their mouth.
Start with:
Why is the mouth open?
Then:
Is nasal breathing comfortable and appropriate?
And finally:
Are there functional patterns that need help changing?
That sequence gets us much closer to addressing the actual problem instead of just what we can see.
About the Author
Reviewed and Written by
Emilee Hyland, RDH
Orofacial Myofunctional Therapist
Founder, Face Value Myofunctional Therapy
Emilee helps children and adults improve breathing, tongue posture, swallowing patterns, oral function, and airway health through personalized Myofunctional Therapy. Her approach emphasizes education, individualized care, and collaboration with dental and healthcare providers.
Wondering Whether Oral Function Is Part of the Picture?
If you've noticed persistent mouth breathing, open-mouth posture, snoring, tongue thrust, or other concerns involving your child's oral function, a conversation with Face Value can help you understand whether a comprehensive Myofunctional evaluation may be an appropriate next step.
Schedule a consultation with Face Value Myofunctional Therapy to learn more.