Why Dogs Sleep With Their Eyes Open: Habit, Instinct, and Awareness

You glance over at your dog mid-nap and freeze. Their eyes are open, glassy, staring at nothing.

Your first thought is probably that something is wrong. Maybe even that you should wake them up.

Many owners think something is off the first time they notice it. It’s an understandable reaction.

A sleeping animal is supposed to have its eyes shut. That’s the whole picture we carry around in our heads.

For many dogs, it’s completely normal.

For most dogs, a half-open stare during sleep is anatomy, not an emergency.

How Dogs Sleep

Dog sleep doesn’t follow the same rhythm as ours. Instead of one long stretch at night, dogs doze in and out throughout the day in short cycles, often lasting less than half an hour at a time.

Within each cycle, a dog moves from lighter sleep into a deeper stage where the body relaxes while brain activity increases.

This deeper stage is where dreaming happens. It’s also where you’ll see the strangest-looking behavior.

A dog in this stage might have paws paddling, ears flicking, or soft whimpers escaping between breaths. Some dogs go still and quiet, twitching through a dream for a few seconds before settling back into calm, even breathing.

None of that is cause for concern on its own. Here’s what each stage typically looks like from the outside.

Light Sleep vs. Deep Sleep

	Light Sleep	Deep Sleep (REM)
Eye appearance	Often closed or barely parted	Half-open with a hazy, relaxed look
Breathing	Slow and even	Can quicken or turn irregular
Movement	Mostly still	Paw paddling, ear flicks, soft sounds
Waking response	Rouses easily, alert almost instantly	Takes a moment to fully wake
What’s happening	Resting, easily interrupted	Dreaming, brain activity picks up

Why Eyes Stay Open

The part that catches most owners off guard is the eyes. Even in a deep sleep, a dog’s outer eyelids don’t always close all the way.

What you’re actually looking at is usually not the eyeball itself. Dogs have a third eyelid, called a nictitating membrane, tucked into the inner corner of each eye.

It’s a thin, protective layer that sweeps across as the eye rolls back during rest. It’s doing most of the work of keeping the surface moist while the outer lid stays slightly parted.

That gives the eye a hazy, half-open look rather than the wide, alert stare people sometimes worry about. The muscles around the eyelids simply relax more than we expect once a dog settles fully into rest.

For most dogs, that relaxation is just part of how their eyes are built. Some breeds show it far more than others, including:

Pugs
Boston Terriers
Shih Tzus

Their shallow eye sockets and naturally prominent eyes make a visible gap much more common than in a dog with a longer nose and deeper-set eyes.

When It’s Normal

Dogs often return to the same familiar napping spots day after day. If your dog wakes up easily and acts like themselves the moment they’re up, the open-eyed look is almost always harmless.

It also tends to show up during naps rather than every single time they sleep. That pattern on its own is reassuring.

A quick, gentle call of their name is usually enough to test things. If they stir, blink, and look around like nothing happened, that’s a dog resting normally, not one in any kind of distress.

When to See a Vet

Most of what shows up during sleep is nothing to worry about. But a few patterns are worth a quick mention at your next vet visit, just so you can rule things out and relax:

Redness, cloudiness, or discharge around the eyes. This is usually just a sign the eye needs a look, not something urgent, but a vet can rule out irritation or infection.
Trouble seeming like themselves after waking. If your dog occasionally seems a little slow to come around, that’s usually fine. If it happens repeatedly or they seem unsteady, it’s worth mentioning so your vet can take a look.
Falling asleep at unusual moments, like mid-meal or mid-play. This is uncommon, and if you notice it more than once, it’s a good thing to bring up so your vet can check in.

None of this is something to diagnose on your own, and it’s rarely an emergency. It’s simply information worth handing to your vet so they have the full picture.

Trust What You’re Seeing, But Watch the Details

Most of the time, a dog sleeping with its eyes open is just a dog resting the way its body was built to rest. The third eyelid is quietly doing its job, the brain is cycling through its usual stages, and nothing underneath that hazy stare needs fixing.

Know the difference between unusual and unhealthy, and you’ll spend a lot less time hovering over a napping dog wondering if you should intervene.

Quick Answers

Is my dog actually dreaming when this happens? Likely, yes. The deeper sleep stage where eyes stay half-open is the same stage linked to dreaming in dogs.

Should I close my dog’s eyes for them? No. Touching a sleeping dog’s face can startle them, and the third eyelid is already handling protection on its own.

Do puppies or senior dogs do this more? Dogs of any age can sleep with their eyes partly open. Individual anatomy, sleep stage, and breed tend to have more influence than age alone.

Behavior Lens

Comfort

Comfort is not simply about sleeping deeply. It is also about finding a level of relaxation that matches the surrounding environment. Dogs naturally adjust how fully they rest depending on how safe, familiar, and undisturbed a situation feels. Sleeping with the eyes partly open can occur as part of this flexible approach to rest, especially during lighter stages of sleep or brief naps. The behavior allows a dog to remain comfortable while still transitioning smoothly between resting and becoming aware of the world again.

Each dog develops its own resting habits through experience. Some readily enter deep sleep in quiet, familiar places, while others spend more time in lighter periods of rest before fully relaxing. Age, routine, and the surrounding environment can all influence these patterns. Seeing a dog asleep with partially open eyes is therefore not always a sign that it is unable to rest. Instead, it highlights how comfort is an active process, with dogs continually adjusting the depth of their relaxation to fit the conditions around them.

Related Behaviors to Explore

Supporting Hub: Social & Routine Behaviors — Daily Patterns That Shape Dogs
Master Hub: Dog Behavior Explained — Complete Guide to Understanding Your Dog

Sources & Further Reading

Adams, G. J., & Johnson, K. G. (1993). Sleep-wake cycles and other night-time behaviours of the domestic dog (Canis familiaris). Applied Animal Behaviour Science, 36(2-3), 233-248. https://doi.org/10.1016/0168-1591(93)90013-F
Bunford, N., Reicher, V., Kis, A., Pogány, Á., Gombos, F., Bódizs, R., & Gácsi, M. (2018). Differences in pre-sleep activity and sleep location are associated with variability in daytime/nighttime sleep electrophysiology in the domestic dog. Scientific Reports, 8, 7109. https://doi.org/10.1038/s41598-018-25546-x
Gelatt, K. N., Gilger, B. C., & Kern, T. J. (Eds.). (2021). Veterinary Ophthalmology (6th ed.). Wiley.
Iotchev, I. B., Kis, A., Turcsán, B., Tejeda Fernández de Lara, D. R., Reicher, V., & Kubinyi, E. (2019). Age-related differences and sexual dimorphism in canine sleep spindles. Scientific Reports, 9, 10092. https://doi.org/10.1038/s41598-019-46434-y
Mitchell, S. C. (2022, April 29). Dog sleeps with eyes open? Here’s why. PetMD. https://www.petmd.com/dog/general-health/why-your-dog-sleeps-their-eyes-open
O’Neill, D. G., Yin, Y., Tetas Pont, R., Brodbelt, D. C., Church, D. B., Pegram, C., & Mustikka, M. P. (2022). Breed and conformational predispositions for prolapsed nictitating membrane gland (PNMG) in dogs in the UK: A VetCompass study. PLOS ONE, 17(1), e0260538. https://doi.org/10.1371/journal.pone.0260538