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18 month sleep regression: signs, causes and what helps

Your easy sleeper now screams at bedtime, wakes at 2 am and refuses the nap. Around 18 months, toddlers are discovering that they are their own person.

By the Swaddle team · Reviewed October 25, 2026

Usual age

17-19 months

Often lasts

Weeks

Is it a problem?

Normal

Signs of the 18 month sleep regression

  • Bedtime battles and stalling
  • Crying when you leave the room
  • Night wakings or very early mornings
  • Refusing or fighting the nap

Why it happens

Several things tend to come together at 18 months:

  • Independence. "No" is a new and powerful word. Testing limits at bedtime is a normal part of development.
  • Separation anxiety often has a second peak around this age.
  • Teething. Canines and first molars often come in between about 13 and 19 months.
  • Language and fears. Toddlers understand much more than they can say, and new fears can appear.

What helps

  1. Keep the one nap. Nearly all 18 month olds still need it. Offer it at the usual time even if they protest.
  2. Give choices inside a fixed routine. Which pajamas, which book. Not whether to go to bed.
  3. Same steps, same order, every night. Predictability lowers the stakes.
  4. Respond calmly and briefly at night, the same way each time.
  5. Treat teething pain as your pediatrician advises, and check with them if your child seems unwell.

How long does it last?

Usually 2 to 6 weeks, longer if it lines up with a big change like a new sibling or daycare.

When to call your pediatrician

A sleep regression is a normal phase. Call your pediatrician if poor sleep comes with fever, breathing that seems hard or noisy, snoring with pauses, vomiting, a rash, ear pulling with fussiness, fewer wet diapers or poor feeding, or if your baby just seems unwell or unlike themselves. Trust your instincts.

Want the whole day mapped out? See the 18 month old sleep schedule.

Questions parents ask

How long does the 18 month sleep regression last?

Most families say 2 to 6 weeks.

Should my 18 month old drop the nap?

No. Most children nap until 3 to 4 years old. Nap refusal at 18 months is usually temporary.

Is it teething or the 18 month regression?

It can be both. Teething usually causes a few rough nights at a time, not weeks. If your toddler has a fever, is pulling at their ears or seems unwell, call your pediatrician.

Sources

  1. Paruthi S, et al. Recommended amount of sleep for pediatric populations: AASM consensus statement. J Clin Sleep Med 2016
  2. Galland BC, et al. Normal sleep patterns in infants and children: a systematic review. Sleep Med Rev 2012
  3. American Academy of Pediatrics: Getting Your Baby to Sleep (healthychildren.org)
  4. American Academy of Pediatrics: Teething: 4 to 7 Months (healthychildren.org)

This page is general information from the sources above, written by the Swaddle team and last reviewed October 25, 2026. It is not medical advice and it is not a substitute for your pediatrician. Every baby is different. If something feels wrong, call your doctor. In an emergency, call 911 (US) or your local emergency number. How we write these pages.

Keep reading

18 month old sleep schedule

Wake windows, naps and a sample day at 18 months.

Wake window calculator

Enter their age and when they woke up. See when the next nap is likely.

4 month sleep regression

Sleep matures into adult-like cycles. More night wakings and 30-45 minute naps.

8 month sleep regression

Crawling, pulling up and separation anxiety collide. Often with the 3 to 2 nap switch.