20 Month Sleep Regression: Why It Happens, How Long It Lasts, and What Helps

If your almost-two-year-old suddenly fights bedtime, cries for you in the night, or wakes up scared when they were sleeping fine last week, you’re not doing anything wrong. The 20 month sleep regression is a real, short-lived bump between the 18 month regression and the 2 year one. It’s driven by big developmental leaps happening all at once: a burst of language, a bigger imagination, a fresh wave of separation feelings, and a toddler who has just discovered they can say no. The good news is that it’s usually one of the briefest disruptions of the toddler year.

Before we go further, the question you came here to answer:

What is the 20 month sleep regression?

The 20 month sleep regression is a temporary stretch of disrupted sleep that shows up in the window between the well-known 18 month regression and the 2 year regression. Unlike the 4 month regression, it isn’t tied to a permanent change in your child’s sleep cycles. By 20 months, sleep architecture is already mature. What changes here is everything happening in your toddler’s mind during the day, and how much of it follows them into the night.¹

“Regression” makes it sound like a step backward, but it’s really the opposite. Your toddler is learning words faster than they can use them, starting to pretend and imagine, and becoming more aware of being separate from you. Those are all signs of a brain that is racing ahead. Sleep just happens to be where a busy brain shows its work.

Why it happens

Several things tend to overlap around 20 months, and they all land on sleep:

• A resurgence of separation awareness. Toddlers this age can hold you in mind when you’re gone, which is wonderful during the day and hard at 2am. Calling for you at night is often about wanting to confirm you’re still there.
• Imagination and the first fears. As pretend play switches on, so does the ability to imagine things that aren’t in the room. This is the age when nighttime fears, and sometimes the first bad dreams or night terrors, can begin.
• A language explosion. New words are arriving daily. The brain does a lot of that consolidation overnight, which can mean lighter, more restless sleep for a week or two.
• Bedtime testing. Around now, toddlers discover that bedtime has edges and that they can push on them. Stalling, extra requests, and the classic “one more” are developmental, not defiance.
• Molars and teething. The second-year molars can be working in around this time and add a layer of nighttime discomfort on top of everything else.

None of these are problems. They’re milestones. And because they’re developmental rather than structural, this regression usually passes quickly once the leap settles.

Signs your toddler is in the 20 month sleep regression

The signs that tend to cluster together at this age are:

• Bedtime resistance in a toddler who used to go down easily: stalling, requests, and refusing to lie down.
• New night wakings, often with crying or calling for you, in a child who had been sleeping through.
• Signs of fear at night, wanting the door open, the light on, or you to stay.
• The first bad dreams, or night terrors where your toddler seems upset but isn’t really awake.
• Early morning wakings, or a nap that suddenly gets shorter or harder to start.
• More daytime clinginess and bigger feelings around every separation.

You don’t need all of them. Two or three showing up together around this age is usually enough to recognize the pattern.

What our data shows

Frequent night waking is most common earlier in the first year and eases as toddlers get older. In our State of Baby Sleep research, the share of children waking several times a night falls steadily after the first-year peak, so by 20 months many toddlers are sleeping through most nights. That’s exactly why a sudden run of wakings at this age stands out so much: it’s a departure from a fairly settled baseline, not a return to newborn life. A few patterns hold up across the toddler families we hear from:

• The families who rode it out fastest were the ones who kept the schedule and the bedtime routine steady rather than overhauling everything in week one.
• Parents who dropped the nap at the first sign of nap resistance often traded a short regression for a longer overtired stretch. At 20 months, almost all toddlers still need that nap.
• The toddlers who settled quickest had boundaries that stayed calm and consistent, so bedtime testing had nothing to push against.
• Most parents who called it “never-ending” were describing a week or two of hard nights. Sleep deprivation stretches time.

“The 20 month regression fools parents because the sleep problem looks new, but the cause is a leap forward. The toddlers who bounce back fastest aren’t the ones whose parents change the most. They’re the ones whose routine and boundaries stay boringly the same while the big feelings pass through.”

If you’d rather see where your specific toddler sits than read more general guidance, that’s what the Betteroo quiz was built for.

What actually helps

Five moves do more during this window than any single new rule. None of them are dramatic. All of them are steady on purpose.

1. Protect the nap and the schedule.

At 20 months, almost every toddler still needs one solid nap. Nap resistance during a regression tempts parents to drop it, but that usually makes nights worse, not better. Hold the nap and a consistent wake time. If you want a reference for the whole day, the 20 month old sleep schedule guide lays out typical timing.

A rough map of a settled toddler day. Ranges are typical; healthy toddlers vary.

Piece of the day	Typical range
Naps per day	1
Nap length  ⭐	about 1.5 to 3 hours
Wake window before bed	about 5 to 5.5 hours
Night sleep	about 10.5 to 12 hours
Total sleep in 24 hours	about 11 to 14 hours

Total-sleep range reflects AASM pediatric recommendations for ages 1 to 2 years.⁴ If your toddler sits at the high or low end, that’s usually fine.

2. Keep the bedtime routine predictable.

A short, unchanging sequence of a few steps, bath or wash, pajamas, a couple of books, a song, lights out, tells a busy toddler brain that the day is closing. During a regression, predictability itself is the intervention. Resist the urge to add new steps under pressure, because you’ll want to keep whatever you add.

3. Answer fears with brief, boring reassurance.

New fears and the first bad dreams are common now. Go in, keep it calm and short, reassure that you’re close, and leave without turning bedtime into a party or a long negotiation. If your toddler seems upset but glassy and hard to wake, that may be a night terror. The kindest response is usually to keep them safe and wait it out rather than fully waking them.

4. Hold your boundaries with kindness.

Bedtime testing is developmental, and it needs something steady to push against. Decide your limits before bedtime, one more hug, one more sip, then the same warm goodnight, and keep them the same every night. Consistency here isn’t strictness. It’s what lets a testing toddler feel safe enough to stop testing.

5. Protect your own sleep.

If there are two adults in the house, take shifts so one of you gets a solid block of sleep. A rested parent handles a testing, fearful toddler with far more patience than an exhausted one, and this regression is short enough that recovery matters more than fairness. This isn’t optimization. It’s getting through the week intact.

What doesn’t help (and what to skip this week)

Equal time on the things that won’t move the needle and may make it worse:

• Dropping the nap. Nap resistance during a regression is not readiness to drop it. At 20 months an overtired toddler sleeps worse at night, not better.
• New habits under pressure. Starting to lie down with your toddler until they fall asleep, or bringing them into your bed for the first time, can quietly become a habit that outlasts the regression by months.
• Big schedule overhauls. If you change bedtime, the nap, the room, and the routine all in one week, you won’t know what helped or hurt. Change one thing at a time.
• Long negotiations at 2am. Reasoning, bargaining, and repeated trips reward the testing. Brief, warm, and boring resolves it faster than long and anxious.

The 20-month regression cheat sheet

If you remember nothing else, remember this: a handful of steady moves help, and a handful of pressure-driven fixes quietly backfire. Screenshot it for the 3am moment.

Steady moves that help, and quick fixes that quietly cost you.

DO THIS Moves that help

1. Keep the one nap and a steady wake time.
2. Hold the same short bedtime routine every night.
3. Answer fears briefly and calmly, then leave.
4. Set limits ahead of time and keep them warm and consistent.
5. Adults take shifts so someone gets real sleep.

SKIP THIS Fixes that backfire

1. Dropping the nap. Resistance isn’t readiness at 20 months.
2. New habits under pressure you’ll want to undo later.
3. Changing five things at once. You won’t know what worked.
4. Long 2am negotiations. They reward the testing.
5. Assuming it’ll last forever. Most settle in a week or two.

Screenshot this for the 3am moment when you need a quick gut check.

When it’s NOT just the regression

The 20 month sleep regression is common, but it’s not the only thing that can disrupt sleep at this age. Talk to your pediatrician, not your sleep app, if any of the following are happening:

• Persistent breathing changes during sleep, such as snoring with pauses, unusually heavy breathing, or mouth breathing that won’t resolve. AAP safe sleep guidance addresses this as a flag worth raising with a pediatrician.²
• Total daily sleep dramatically below the AASM range (roughly 11 to 14 hours including the nap at this age) across multiple weeks, not single bad nights.⁴
• Missed developmental milestones alongside the sleep change, or a clear loss of words or skills.
• Signs of pain that escalate at night, such as ear tugging with fever, or teething that seems far more intense than usual.
• A sudden change in alertness, tone, or temperature.

Outside of those, what you’re experiencing is almost certainly the regression. Tiring, but typical.

A note on sleep training during the regression

By 20 months, structured behavioral sleep approaches are well within the age range the research studied, so a regression isn’t a reason to rule them out.³ The catch is timing. Launching a brand-new method in the thick of a short, fear-driven regression often adds stress for everyone. If your toddler had solid sleep habits before this bump, the faster path is usually to hold your routine and boundaries steady and let the leap pass.

If sleep was already a struggle before 20 months and you want to make a real change, the common sleep training methods guide walks through what the research actually says about each approach.

Frequently asked questions

Key takeaway

The 20 month sleep regression is a short, developmental bump between the 18 month and 2 year regressions. It’s not a defect, you didn’t cause it, and it isn’t a permanent change in how your toddler sleeps. Protect the nap, hold a predictable routine, answer fears briefly, keep your boundaries warm and consistent, and take shifts so you can stay patient. For most toddlers, that’s most of what separates a one-week regression from a three-week one.

Want hands-on help near you? Betteroo maintains verified directories of baby sleep consultants in 11 US cities, every listing checked monthly against the consultant’s own site and certifying program, with transparent pricing. Browse sleep consultants by city or see what a sleep consultant costs.