6 Month Old Suddenly Won’t Sleep Through the Night

If your baby suddenly stopped sleeping the way they used to, you are not imagining it.

Around 6 months, sleep often becomes lighter, more fragmented and much less predictable than before — even for babies who were previously sleeping well.

And while it can feel like something has “gone wrong,” this stage is usually connected to rapid neurological and developmental change rather than bad habits or failed routines.

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Things to Check First

Before assuming this is purely developmental, it’s worth ruling out a few simple factors first.

Things like teething, illness, congestion, feeding changes, overtiredness or changes in the sleep environment can all affect sleep more noticeably around this age.

If your baby seems unusually distressed, uncomfortable or in pain, it’s always worth speaking with your GP or health visitor.

Once physical discomfort or environmental changes are ruled out, the most likely cause is usually development rather than something being “wrong.”

If you’re currently supporting more night waking or feeding overnight, this can help you do it safely
→ Co-Sleeping With a Baby: Bedsharing Safety Guide for New Parents

Once you’ve ruled out physical discomfort or environmental factors, the most likely cause is usually development rather than something being “wrong.”

Why Sleep Changes So Suddenly Around 6 Months

Around 6 months, babies go through several major developmental shifts at the same time.

They become more aware of their surroundings, more sensitive to separation, more physically active, and their sleep cycles begin maturing into a lighter, more adult-like pattern.

Because of this, sleep often becomes:

• lighter
• less predictable
• easier to disrupt
• more dependent on reassurance and comfort

Even babies who previously slept long stretches may suddenly begin:

• waking more frequently
• resisting sleep they previously accepted
• needing more support to settle
• waking fully when transferred

This stage is often called the “6 month sleep regression,” but in most cases it is less of a regression and more of a developmental transition.

Sleep is changing because your baby is changing.

And while it can feel sudden and exhausting, these shifts are extremely common at this age.

If your baby also wakes immediately when put down, this is often closely connected to lighter sleep cycles and increased awareness:
→ Baby Wakes Up When Put Down — Here’s Why (And What Actually Helps)

What Actually Helps

The goal at this stage is usually not “fixing” sleep overnight.

More often, it is helping your baby move through a period of rapid neurological and developmental change with as much calm and predictability as possible.

And interestingly, the things that help most are often surprisingly simple:
less stimulation, more consistency and realistic expectations for this age.

1. Keep Evenings Lower-Stimulation

Around 6 months, babies become much more sensitive to their environment before sleep.

Bright rooms, loud activity, screens or busy evenings can make it harder for the nervous system to settle fully.

Often, a slower final hour before bed helps more than adding complicated routines.

Soft lighting, quieter play and calmer transitions into sleep usually work best at this age.

Some parents also find that a dimmable night light helps overnight feeds and settling feel less disruptive without fully waking the room.

2. Try Not to Overtire Them

Overtiredness can build surprisingly quickly around this age.

And interestingly, babies who seem suddenly “wide awake” at bedtime are sometimes actually overstimulated or overtired rather than under-tired.

If sleep has become particularly difficult, a slightly earlier bedtime for a few nights can sometimes help things feel more manageable again.

3. Keep Night Waking Calm and Predictable

When babies wake overnight, the goal is usually helping them return to sleep without fully activating the nervous system.

Keeping interactions quieter and more predictable often helps:

• dim lighting
• slower movements
• calm responses
• minimal stimulation during feeds or changes

At this age, less stimulation overnight often leads to easier resettling.

4. Avoid Constantly Changing Approach

When sleep suddenly becomes unpredictable, it’s very easy to start changing everything at once:

• new schedules
• new routines
• new sleep advice
• new expectations

But often, constant adjustment creates more stress for both the parent and the baby.

Usually, consistency matters more than perfection.

5. Expect More Reassurance-Seeking

Around 6 months, babies become much more aware of separation and connection.

That often means they suddenly need more reassurance overnight, even if they previously slept more independently.

This is not usually a sign that you’ve created bad habits.

Your baby’s awareness is changing — and sleep is often where that becomes most noticeable.

What Not to Do

You don’t need to rush into “fixing” sleep, remove comfort, or push independence before your baby is ready.

At this stage, responsiveness and consistency often support sleep more effectively than constant adjustment.

When Does This Phase End?

For most babies, this stage gradually settles.

You may notice:

• longer stretches returning
• easier settling
• fewer night wakings

It doesn’t happen overnight.

But it does shift.

Final Thoughts

This stage can feel exhausting, especially during long nights and unpredictable sleep.

But the same developmental changes disrupting sleep now are also supporting awareness, movement, and independence later on.

Even if it doesn’t feel like it at 3am.

Frequently Asked Questions About 6 Month Sleep Changes

Why is my 6 month old suddenly waking at night?

Night waking often increases around 6 months due to development.

Your baby is becoming more aware, learning new physical skills, and transitioning into more mature sleep cycles.

This can make sleep lighter and more easily disrupted — even if they previously slept well.

Is the 6 month sleep regression real?

What’s often called a “sleep regression” is actually a developmental shift.

Your baby’s sleep is becoming more structured and adult-like, which can temporarily lead to more waking.

It’s not a step backwards — it’s a sign of progress.

Why does my 6 month old wake every 2 hours?

Frequent waking can happen when sleep cycles change.

Your baby may now wake more fully between cycles and need support to settle again.

Other factors like hunger, development, or overtiredness can also contribute.

Should a 6 month old be sleeping through the night?

Some babies do — but many don’t.

Night waking at this age is still very normal.

Sleep patterns vary widely, and waking doesn’t mean something is wrong.

Why is my 6 month old harder to settle at bedtime?

Increased awareness can make bedtime feel different.

Your baby may notice more about their surroundings, resist separation, or feel more alert.

This can make settling take longer than before.

Could teething cause night waking at 6 months?

Yes — teething can affect sleep.

Discomfort, even mild, can make it harder for your baby to settle or stay asleep.

This is often temporary and tends to pass as symptoms ease.

How long does the 6 month sleep phase last?

This stage doesn’t have a fixed timeline.

For many babies, sleep gradually improves over a few weeks as they adjust to developmental changes.

It tends to ease rather than suddenly stop.

What helps a 6 month old sleep better at night?

Simple, consistent support makes the biggest difference:

• a calm, predictable sleep environment
• consistent routines
• responding gently to night waking
• avoiding overstimulation

Over time, this helps your baby feel secure and settle more easily.