Why Do Babies Smile in Their Sleep?

Newborns will typically sleep 14 to 17 hours per day, usually scattered throughout the daytime and nighttime, says Dr. Combs. Over time, sleep will gradually decrease and move toward a more consistent schedule in terms of nighttime sleep and nap schedules.2

How to Encourage Your Baby to Smile When They're Awake, Too

To help your baby learn to smile, you may consider talking, singing, and laughing with them—and smiling yourself, too. “Even at a young age, they learn to mirror expressions and emotions around them, setting the groundwork for parental attachment and self-confidence as they mature,” says Dr. Priest, adding that intentional smiling tends to occur as early as two months old.3 “Babies begin to spend more time awake and more time focusing on the familiar faces around them.”

Your baby will start to discover that facial expressions are a way of having “conversations” with you. Smiling is also another means of expressing their needs, in addition to crying.4 (Which they’ve already mastered so well!)

When you respond quickly and enthusiastically to your baby’s smiles, it lets them know they are important, which is essential for trust-building.4 Babies may initiate smiling (often accompanied by adorable gurgling noises), or respond to yours. Have fun with it! Make funny faces, stick out your tongue, and keep the “conversation” engaging and expressive.

Should I Ever Worry About My Baby Smiling in Their Sleep?