Your eyes water when you yawn because the facial muscles involved in yawning physically squeeze the glands that produce tears. It’s a mechanical side effect, not a sign of sadness or eye problems. Nearly everyone experiences it to some degree, and it’s completely normal.
How Yawning Squeezes Out Tears
Your tear-producing glands, called lacrimal glands, sit just above and to the outer side of each eye. When you yawn, your face goes through a surprisingly intense muscular contraction. Your jaw stretches wide, your cheeks pull tight, and the muscles ringing your eyes clench. That ring of muscle around each eye presses directly against the lacrimal glands, essentially wringing them out like a sponge.
At the same time, the tiny drainage tubes near the inner corners of your eyes, which normally funnel tears down into your nose, also get squeezed shut. So you’re dealing with a double effect: more tears being pushed out of the glands and fewer tears draining away through the normal plumbing. The result is tears pooling on the surface of your eye, sometimes enough to spill over onto your cheeks.
As a researcher at Washington State University put it, yawning contracts all the muscles in your face at once, squeezing tears out of both the glands and the drainage tubes simultaneously.
These Tears Aren’t Different From Normal Tears
You might assume that reflex tears, the kind triggered by yawning, onions, or wind, have a different makeup than the baseline tears constantly coating your eyes. Research published in the International Journal of Applied and Basic Medical Research found no meaningful difference. Basal tears (the ones always present) measured about 308 mOsm/L, while reflex tears came in at 306 mOsm/L. The concentration of electrolytes stayed essentially the same regardless of how the tears were triggered.
This means yawning tears provide the same lubrication and protection as your regular tear film. They just show up in a larger, more noticeable volume because they’re being mechanically forced out rather than slowly secreted.
Why Some People Tear Up More Than Others
Not everyone gets visibly watery eyes from yawning, and the difference comes down to individual anatomy. People with larger lacrimal glands or tighter orbicularis oculi muscles (the ring around the eye) may produce a bigger surge of tears. The shape of your face, the width of your yawn, and even the size of your drainage ducts all play a role.
If you tend to yawn with your whole face, mouth wide open and eyes scrunched, you’re compressing those glands harder and blocking the drainage more completely. A smaller, more restrained yawn involves less facial contraction and typically produces fewer tears. You can test this yourself: a full, uninhibited yawn will usually water your eyes more than a polite, closed-mouth one.
A Possible Cooling Function
There’s one additional theory worth noting. Some researchers have proposed that the tearing during yawning may help dissipate heat from the skull. Yawning itself is thought by some scientists to function partly as a brain-cooling mechanism, with the deep inhalation of cooler air helping regulate temperature. The thin layer of tears spreading across the eye surface could contribute a small additional cooling effect through evaporation. This remains a hypothesis rather than an established fact, but it suggests the tearing may not be purely accidental.
When Excessive Tearing Points to Something Else
Watery eyes during yawning are normal. Watery eyes all the time, or tearing that seems disproportionate to the trigger, can signal a different issue. The most common culprit is a partially blocked nasolacrimal duct, the drainage channel running from your inner eye corner down into your nose. When that tube narrows or clogs, tears back up and overflow even without yawning.
Signs that something beyond normal mechanics is going on include tearing that happens constantly throughout the day, discharge that looks cloudy or yellowish, swelling or tenderness near the inner corner of the eye by the nose, or tears tinged with blood. A history of sinus surgery, facial trauma, or chronic sinus infections can increase the risk of duct obstruction. Certain eye medications used long-term can also cause the drainage openings to narrow over time.
If your tearing is limited to yawning, laughing, or similar facial expressions and resolves within seconds, there’s nothing to investigate. Your facial muscles are simply doing what they do, and your tear glands are along for the ride.