The 18 month sleep regression: separation, "no" and bedtime

The 18 month sleep regression shows up around 77 to 83 weeks as bedtime protests, new night wakings or refused naps. It usually lasts 1 to 2 weeks, and plenty of toddlers skip it. When it comes, bedtime takes the hit: separation, new words and a new interest in saying no all meet there.

What causes the 18 month sleep regression?

Sources don’t agree on a single trigger for this window, and some don’t treat regressions as fixed events at all. What they do describe is a lot changing at once around 18 months, and most of it lands at bedtime.

Three things meet at bedtime

1. 1 Separation, again Many toddlers start missing you more at 15 to 18 months.
2. 2 New words Most are trying three or more words by 18 months.
3. 3 Testing limits One more book, more water, another hug.

• Separation, again. Many toddlers who skipped separation anxiety as babies start showing it at 15 or 18 months. For others, the phase that began around 8 or 9 months is still going. Bedtime is the longest goodbye of the day.
• New words. By 18 months most toddlers are trying to say three or more words besides “mama” or “dada”, and by 2 most put two words together. A newly talkative toddler doesn’t always want the day to end.
• Testing limits. One more book, more water, another hug. Stalling that happens nearly every night, with nothing wrong at any other time of day, is limit testing. It comes and goes, and it can return weeks or months later. Toddlers settle on whichever request gets the most predictable answer.

It’s the fifth of the common sleep regression ages: 4 months, 6 months, 8 to 10 months, 12 months, 18 months and 2 years. It comes after the 12 month regression and before the 2 year one.

18 months is the fifth common window

4m

6m

8–10m

12m

18m

2y

birthage 2

1. 4 months
2. 6 months
3. 8–10 months
4. 12 months
5. 18 months separation, limits
6. 2 years

About 77 to 83 weeks old. Not every toddler has it.

How long does the 18 month regression last?

Usually 1 to 2 weeks. If bedtime is still a battle after about a month, the regression itself has likely passed and something else is holding the pattern in place: a schedule that no longer fits, or a way of getting through the rough nights that has become the routine, such as lying down until they fall asleep or one more story every time. That isn’t a mistake. It’s a choice you can keep or change gently.

Should an 18 month old be on one nap?

Most are. About 77% of toddlers have moved to one nap by 18 months, up from about 56% at 15 months. By 2 years, about 95% have.

18 months, one nap

5–6 h

02 h4 h6 h

Awake between sleeps on one nap.

On one nap, most 18-month-olds are comfortable awake for 5 to 6 hours between sleeps, with 1.5 to 2.5 hours of day sleep and 10 to 12 hours at night. Bedtime usually falls between 7:00 and 8:30 pm, most often around 7:30. Across 24 hours, that adds up to the 11 to 14 hours recommended for 1- and 2-year-olds.

If your toddler still takes two naps and nights are fine, nothing says one has to go this week. If naps have turned short or bedtime keeps drifting late, the move to one nap may be what the “regression” is really about. Sleep regression or dropping a nap covers how to tell.

A refused nap at 18 months doesn’t mean your toddler is done napping. Almost all children under 3 still need one.

What helps

1. Keep the routine the same every night, in its steps and its length. A consistent bedtime routine is linked to better sleep in young children, and the more nights it happens, the stronger the link. At this age, making it 5 to 10 minutes longer than before often helps.
2. Give it a clear ending. A warning near the end (“two more pages”), the same goodnight words every night, and then you leave the room, not your toddler. Once the books are done, they’re done.
3. Build the requests in. The drink, the bathroom trip, the last hug: make them steps of the routine instead of answers to calls from the crib. Giving in only sometimes is what keeps the stalling going.
4. Make goodbyes predictable. Don’t sneak out once your toddler is asleep, since waking to find you gone can teach them to fight sleep and look for you. In the day, play games of stepping out of sight and coming straight back.
5. Invite a favorite toy. Many toddlers adopt one between 12 and 18 months, and from 12 months a small soft toy can stay in the crib.
6. Keep the night response steady. Whatever helps your toddler fall asleep at bedtime is what they look for at each waking.

Some night waking is still normal at this age: anywhere from none to two or more wakings a night falls within the normal range for 1- to 2-year-olds.

Behavioral: keep the routine steady and the limits at bedtime clear and kind, and stay consistent through the pushback. Responsive: make bedtime something you do together, talk your toddler through it, and lean on a comfort object and extra closeness while it passes. Both work; consistency matters more than the choice.

If you use tiho+, your toddler’s plan holds bedtime steady through a regression instead of moving it after every short nap.

Where the advice differs. Some sources name 18 months as a regression window. Others don’t describe age-based regressions at all, and look for a specific cause instead: a schedule that no longer fits, limit testing, or a change at home. Sources also differ on naps: one view holds that two naps at 18 months is one too many, while others treat one or two naps as normal until about 2. tiho’s plan moves to one nap at 15 months and reads your toddler’s own log for the timing.

When to talk to your pediatrician

Check in if new wakings come with fever, ear pulling, poor eating or unusual sleepiness, if your toddler snores loudly or seems to pause in breathing during sleep, or if sleep is still very disrupted after a few weeks with no change at home, illness or new skill to explain it.

Related reading

• Sleep regressions by age
• The 12 month sleep regression
• The 2 year sleep regression
• Sleep regression or dropping a nap? How to tell
• Dropping a nap: the 3-to-2 and 2-to-1 transitions