Why Sleep Training Between 18–24 Months Can Be So Challenging (and What You Can Do About It)
- Brittney Koleszarik
- Jul 14
- 2 min read
If your toddler is suddenly fighting bedtime, waking all night, or refusing naps between 18 and 24 months… you're not alone. This age range is one of the most difficult windows to sleep train—and there are some very real developmental reasons why.
Let’s break it down.
1. Cognitive Leaps & New Awareness
Between 18–24 months, your toddler's brain is exploding with growth. They’re becoming more aware of their surroundings, their preferences, and their ability to say no. This awareness makes them more resistant to routines and limits—including bedtime.
They realize you leave the room—and they don’t like it.
2. Separation Anxiety Makes a Comeback
While separation anxiety usually peaks around 9 months, it often resurfaces around 18 months. Toddlers begin to feel more emotionally attached and more fearful of being apart from their caregivers.
Cue: crying at bedtime, middle-of-the-night wakeups, and the sudden refusal to nap unless you stay close.
3. Language Bursts Lead to Power Struggles
Toddlers at this stage are learning dozens of new words, but their ability to express big emotions still lags behind. They’re caught between wanting independence and still needing a lot of help.
So bedtime turns into a battle of wills.
They may not be able to say “I feel overwhelmed,” but they can definitely scream “NO!” when it’s time to put on pajamas.
4. Sleep Needs Are Shifting
Around 18 months, most toddlers transition to one nap per day. If this isn’t timed well, they can become overtired, leading to bedtime resistance and night wakings.
Too much daytime sleep = hard bedtime.
Too little = overtired toddler = early wakings and crankiness.
It’s a delicate balance.
5. Habits Are Now Strongly Cemented
If your toddler has been co-sleeping, needing to be rocked to sleep, or waking for comfort feeds—those habits are now deeply ingrained. Toddlers are smart, persistent, and less flexible than infants when it comes to change.
That doesn’t mean sleep training is impossible—but it does mean it may take longer, require more consistency, and possibly bring a few more tears.
👩⚕️ So… What Can You Do?
As an RN and certified pediatric sleep consultant, I always remind parents that you’re not doing anything wrong—this stage is just hard. But there is a path forward.
💡 Here’s what helps:
Stay consistent with your bedtime routine. Toddlers need structure.
Acknowledge emotions (“I know it’s hard to say goodnight. I’m right here.”).
Give choices during the routine (pajamas, books, etc.) to reduce power struggles.
Be confident in your boundaries—toddlers feel safest when you’re calm and consistent.
Get support if sleep isn’t improving—sometimes a customized plan is what’s needed.
💜 Final Thoughts
If your toddler is in this tricky 18–24 month phase, know this: You’re not alone, and this phase doesn’t last forever. With the right tools and support, you can absolutely help your little one learn to sleep well—and reclaim your evenings again.
Need help building a plan that works for your toddler’s unique personality and needs? I’d love to support you.
Reach out anytime or book a free discovery call with me
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