Yes, there is a sleep regression around 12 months, and it’s one of the more common ones parents encounter during the first year. If your baby was sleeping well and has suddenly started fighting bedtime, waking more at night, or refusing naps, the timing lines up with a well-recognized pattern tied to the enormous developmental changes happening near the first birthday.
What the 12-Month Sleep Regression Looks Like
The 1-year sleep regression typically shows up as some combination of bedtime resistance, more frequent night wakings, shorter naps, or skipping naps entirely. A baby who previously went down without much fuss might suddenly cry when placed in the crib, stand up and refuse to lie back down, or wake at 2 a.m. fully alert and ready to practice new skills. Some babies start waking earlier in the morning, too.
Not every baby goes through it. Some sail past the 12-month mark with no disruption at all. Others hit it closer to 11 months or not until 13 months. The timing varies because it’s driven by developmental milestones, and babies don’t all reach those milestones on the same schedule.
Why It Happens
Around the first birthday, babies are going through a staggering amount of change at once. They’re pulling to stand, cruising along furniture, or taking first steps. They’re beginning to understand and use words. Their emotional awareness is expanding rapidly, meaning they’re more tuned in to your presence and more distressed by your absence. All of this overlaps in a short window, and the result is a brain and body that are too busy to settle easily into sleep.
Physical restlessness plays a big role. Babies who are learning to walk or stand often practice these skills involuntarily, even in the crib in the middle of the night. Their bodies are wired to rehearse new motor patterns, and sleep suffers as a result. You may find your baby standing in the crib, fully awake, unsure how to get back down.
Separation anxiety also peaks around this age. Your baby now understands that you exist even when you leave the room, but doesn’t yet grasp that you’ll reliably come back. This makes bedtime feel like a genuine loss to them. The heightened emotional engagement that comes with being nearly a year old means bigger reactions at sleep transitions, whether that’s the initial bedtime separation or a 3 a.m. wake-up where they realize they’re alone.
Teething can pile on, too. Many babies are cutting their upper and lower front teeth or their first molars around 12 months, which causes gum soreness that tends to be worse at night when there are fewer distractions.
How Long It Lasts
Most 12-month sleep regressions last between 2 and 6 weeks. The wide range depends on how many developmental milestones are converging at once and how you respond to the disruption. Parents who make major changes to sleep routines during a regression (like bringing the baby into their bed for the first time or introducing new sleep associations) sometimes find the disruption lingers longer because the baby adopts new expectations.
If sleep problems persist well beyond 6 weeks, something else may be contributing. Ear infections, for example, are common at this age and cause pain that worsens when lying down. Ongoing sleep disruption that doesn’t improve is worth mentioning to your pediatrician.
The Nap Transition Trap
One of the trickiest parts of the 12-month regression is that it looks a lot like your baby is ready to drop from two naps to one. A baby who suddenly refuses their second nap for a week straight seems like they’re telling you they only need one nap now. But most sleep experts agree that the transition to one nap typically happens between 14 and 18 months, not at 12 months. Dropping to one nap too early often backfires: the baby becomes overtired, which makes nighttime sleep even worse.
If your baby is fighting a nap, try adjusting the timing by 15 to 30 minutes before eliminating it. An overtired 12-month-old is harder to get to sleep than a well-rested one, which is counterintuitive but consistently true.
What Actually Helps
The most effective approach is also the least satisfying: stay consistent. Keep your existing bedtime routine intact, even when your baby protests it. A predictable sequence of events (bath, book, song, crib) gives your baby a reliable signal that sleep is coming, and that predictability matters more during a regression than at any other time.
For the physical restlessness, give your baby plenty of opportunity to practice new motor skills during the day. If they’re learning to stand, let them practice pulling up and sitting back down repeatedly during playtime. The more they master these movements while awake, the less their brain needs to rehearse them at night.
For separation anxiety, brief check-ins work better than either ignoring your baby completely or picking them up and rocking them to sleep each time. Going in, offering a calm voice and a brief pat, then leaving again teaches your baby that you’re nearby without creating a new sleep association that will be hard to undo later. Some parents find that leaving a worn t-shirt in the crib (tied to the slats, not loose near the baby’s face) provides a comforting scent.
Keep the sleep environment boring. At 12 months, babies are far more aware of their surroundings than they were at 6 months. A dark room with white noise and minimal stimulation gives them less reason to stay awake and explore. If your baby can now stand in the crib and see interesting things around the room, consider whether the space needs to be simplified.
Feeding Changes and Night Waking
Many families are adjusting feeding patterns around the first birthday, whether that means weaning from breastfeeding, transitioning off formula, or introducing cow’s milk. These changes can affect sleep independently of the regression itself. Research on toddler diets has found that breastfeeding is associated with more frequent night waking, so families who are still nursing at 12 months may see more disruption than those who aren’t.
Interestingly, higher intake of dairy products (milk, cheese, yogurt) in toddlers has been linked to increased odds of night waking as well. This doesn’t mean you should avoid dairy, but it’s worth noting that the dietary shift happening around the first birthday can be its own sleep disruptor, separate from developmental causes. Making sure your baby is eating enough during the day, particularly at dinner and before bed, can reduce hunger-driven wake-ups.
How It Compares to Other Sleep Regressions
The 12-month regression tends to be shorter and less intense than the 4-month regression, which involves a permanent change in sleep architecture. At 4 months, a baby’s sleep cycles reorganize to resemble an adult pattern, which is why that regression often feels like everything breaks at once. The 12-month version is more of a temporary disruption layered on top of an already-established sleep pattern.
It also differs from the 8-month regression, which is more heavily driven by separation anxiety and less by motor development. At 12 months, you get both at the same time, plus teething, plus potential feeding changes. The silver lining is that because this regression has so many contributing factors, each one resolves on its own timeline, and sleep usually improves gradually rather than staying bad until everything clicks at once.