An Age-by-Age Guide to Sleep Training

Parents often wonder when to sleep train their little one—but as it turns out, the answer isn’t clear cut. "There are good times to sleep train and periods when it may be less likely to work," says developmental psychologist Isabela Granic, Ph.D., coauthor of Bed Timing: The 'When-To' Guide to Helping Your Child to Sleep. "This is because infants and toddlers go through mental growth spurts that make them especially clingy, fussy, and prone to night wakings. They're learning new cognitive skills and often don't sleep as well."

Keep reading for Dr. Granic’s explanations of what's happening developmentally as your baby grows, and how to choose the best month to introduce sleep training.

Newborn-2.5 Months

Newborns can't tell the difference between night and day because they don't produce enough melatonin. They also require frequent night feedings. Because of this, parents should hold off on sleep training for now.

3-4 Months

By 3 to 4 months, infants are forming a nighttime sleep cycle. They’re more sociable, don’t usually suffer from separation anxiety, and start snoozing better. However, most 3- and 4-month-olds aren't developmentally ready to self-soothe, so sleep training may be difficult.

4.5-5.5 Months

Most experts recommend sleep training around this time, when babies can make it 6 to 8 hours without feeding overnight. But keep in mind that your little one is learning that crying gets a response from you—so expect plenty of waterworks when you leave the room!

6-8 Months

Babies are more interested in reaching for toys than keeping their eyes fixed on you. If you’re thinking about sleep training, Dr. Granic says to go for it. As a bonus, your baby may not be as fussy when they wake at night.

9-11 Months

At 9 to 11 months, an infant starts understanding that parents still exist after they leave the room. Knowing you're just outside the door can spark tears, so sleep training can be frustrating. There’s nothing stopping you from trying, though.

12-16 Months

As toddlers focus on developing speech and physical skills, they're less clingy with Mom and Dad. This is another good time to sleep train, says Dr. Granic.

17-21 Months

It sounds counterintuitive, but a child's budding independence makes them more needy. Hold off on sleep training for now.