Why Kids Keep Their Mouth Open (and What It Means for Their Health)
Many parents worry about why their child’s mouth is always open or why their child prefers to breathe through their mouth instead of their nose. This is known as open mouth posture, and while it might look harmless, it can have a bigger impact on your child’s health and development than you might think.
Open mouth posture is often linked to mouth breathing in kids, speech difficulties, changes in facial growth, and even poor sleep quality. The good news is that there are proven mouth breathing solutions that can help your child achieve healthy lip closure and proper tongue posture. In this guide, we’ll cover what open mouth posture really means, why it happens, how to tell if it’s just a habit, and the benefits of addressing it early with the right oral habits and myofunctional therapy exercises.
What Is Open Mouth Posture?
Open mouth posture is when a child’s lips stay apart for most of the day, even when they are not talking, eating, or breathing heavily. Instead of the lips resting gently together with the tongue up on the roof of the mouth, the mouth stays open—sometimes just a little, sometimes quite a lot.
This may not seem like a big deal at first. Many parents assume their child is just “relaxed” or “focused.” But when open mouth posture happens all day, every day, it can impact how the face grows, how teeth come in, and even how a child sleeps and speaks.
In an ideal resting posture:
Lips are gently closed.
Teeth are slightly apart.
Tongue rests lightly against the roof of the mouth.
Breathing happens quietly through the nose.
When this pattern isn’t happening, it’s worth looking into why.
Common Causes of Open Mouth Posture
There’s no single cause for open mouth posture—most of the time, it’s a mix of factors. Here are the most common ones:
1. Chronic Nasal Congestion
If your child can’t breathe easily through their nose, they will naturally open their mouth to get more air. Allergies, enlarged adenoids or tonsils, and frequent colds can all make nasal breathing harder.
2. Tongue Tie or Low Tongue Posture
A tongue tie (restricted lingual frenulum) can make it hard for the tongue to rest against the roof of the mouth. If the tongue sits low in the mouth, the lips often part to make room.
3. Oral Habits
Thumb sucking, pacifier use past infancy, or even nail biting can change the way the lips and tongue rest, leading to an open-mouth habit.
4. Weak Oral Muscles
Sometimes kids simply don’t have strong enough muscles around the lips and cheeks to keep the mouth comfortably closed.
5. Structural or Airway Differences
A small jaw, deviated septum, or other airway differences can make nasal breathing difficult and encourage mouth breathing.
How It Affects Facial Growth, Teeth & Speech
Open mouth posture is more than just a cosmetic issue—it can affect your child’s overall development.
Facial Growth
When the mouth stays open, the tongue isn’t supporting the roof of the mouth. This can lead to a narrow palate, longer face shape, and changes in how the jaws develop.
Teeth Alignment
Mouth breathing and open mouth posture often lead to crowded teeth, open bites, or overbites. Orthodontists often see these patterns in kids who have been mouth breathers for years.
Speech Development
The tongue plays a key role in forming sounds like /t/, /d/, /n/, and /l/. If it’s not resting in the right place, these sounds can become distorted, and kids may develop speech delays or articulation errors.
Sleep Quality
Open mouth posture is often linked with snoring or even pediatric sleep-disordered breathing. Poor sleep can affect mood, focus, and learning.
Open Mouth Posture vs. Simple Habit: How to Tell
Sometimes a child keeps their mouth open simply because it has become a habit but often, there’s an underlying reason.
Ask yourself:
Can your child close their lips easily when you remind them?
Do they keep their mouth open even when watching TV or playing quietly?
Do they snore or breathe noisily at night?
Do they often have dry lips or bad breath?
If they can close their mouth but just forget to, it might be habit-based. But if closing their mouth looks uncomfortable or forced, there may be a structural or functional reason that needs attention.
When to Worry & Seek Help
See a professional if you notice:
Persistent open mouth posture that doesn’t improve with reminders.
Frequent congestion, snoring, or restless sleep.
Speech delays or unclear speech.
Changes in facial growth or bite.
Behavioral signs of poor sleep (hyperactivity, irritability).
A pediatrician, ENT (ear, nose, and throat doctor), or airway-focused dentist can check for nasal blockages or structural issues. A myofunctional therapist can assess tongue posture, muscle strength, and oral habits.
Myofunctional Therapy Exercises to Encourage Lip Closure
Myofunctional therapy is like physical therapy for the muscles of the mouth, face, and tongue. Here are a few simple exercises you can try (under professional guidance):
Button Pulls
Place a button on a string between your child’s lips (not teeth) and have them gently hold it in place with lip strength.
Tongue to Spot
Teach your child to place the tip of their tongue on the “spot” (just behind the upper front teeth) and hold it there while keeping lips closed.
Bubble Blowing
Blowing bubbles or using whistles strengthens the muscles around the lips and encourages nasal breathing.
Lip Closure Practice
Set a timer for a few minutes during screen time and challenge your child to keep their lips together and breathe quietly through their nose.
Professional myofunctional therapy programs are individualized and include fun, engaging exercises to make the process easier for kids.
Long-Term Benefits of Correcting Open Mouth Posture
Correcting open mouth posture isn’t just about appearance—it supports overall health and well-being.
Better Facial Development: Supports natural jaw growth and facial symmetry.
Improved Dental Health: Helps prevent crowding and orthodontic relapse.
Clearer Speech: Allows the tongue to work efficiently for sound production.
Better Sleep: Promotes nasal breathing, which supports deeper, more restorative sleep.
Confidence Boost: Kids who can breathe easily and speak clearly often feel more comfortable socially.
Key Takeaways for Parents
Open mouth posture is more than a habit. It can signal airway issues, tongue posture problems, or weak oral muscles.
Mouth breathing in kids can affect growth. It impacts jaw development, teeth alignment, and speech clarity.
Look for the root cause. Chronic congestion, oral habits, or tongue tie might be contributing factors.
Early action matters. Addressing issues now can prevent long-term dental, speech, and sleep problems.
Simple exercises can help. Myofunctional therapy supports healthy oral posture and nasal breathing.
If your child frequently keeps their mouth open, it’s worth taking a closer look. Early intervention can make a big difference for their health, speech, and confidence.
With the right guidance whether it’s clearing nasal congestion, strengthening oral muscles, or starting myofunctional therapy, your child can learn to breathe through their nose and keep their lips closed naturally.
Ready to Take the Next Step?
If you’re concerned about your child’s open mouth posture or mouth breathing, schedule a consultation with us. We’ll assess your child’s breathing, tongue posture, and oral habits, and create a personalized plan to support healthy growth and better sleep.
👉 Book a Myofunctional Therapy Consultation today and help your child breathe easier and thrive.
