When Do Babies Start Sitting Up? A Pediatric Expert Answers

In general, babies start to sit with support between four and six months of age. “This is the stage when a baby can sit in your lap while you hold them, but their sitting continues to advance until they can tripod and eventually sit upright, unsupported, which typically occurs by nine months of age,” says Dr. Jarret. Basically, if your baby can hold their own head up by the age of four months—and they should be able to—then they’re on their way to developing the muscles and balance they need to sit up independently. From that point forward, you can expect to see fairly rapid motor skill development. If you have further questions about motor skill milestones, you can find all the information on the Center for Disease Control website.

How Do Babies Learn to Sit Up?

As mentioned, a baby’s ability to support their own head (i.e., hold it up and look around) is a key indicator that they’re getting ready to sit up and are likely capable of doing so with some support from you. It’s a good idea to regularly spend time with your baby in a seated position, so you might consider making it part of your daily routine to have your baby seated in your lap while you read them a book, etc. 

When it comes to helping your baby sit up, the expert has a few suggestions:

• Lap sitting is a good first step that, as it sounds, involves supporting your baby in a seated position in your lap.

• Independent supported sitting is another teaching strategy in which you place your baby in a seated position that they wouldn’t have been able to achieve on their own (i.e., passive sitting) and then help them maintain the position by surrounding them with pillows and other supports so they don’t tip over.

• Active play time, also called tummy time, is another expert-approved method that can be introduced once your baby has good head control, and its benefits are well-documented. It’s also a great way to prime your baby for independent sitting: “If they can lay on the floor prone with their chest off the floor, they can sit,” says Dr. Jarret, adding that “giving your baby active play time on the floor allows them to develop the muscles that become important for sitting, crawling, standing and walking.” (Experts recommend starting with two to three short—as in, 3 to 5 minutes max—sessions per day, gradually working your way toward longer sessions, with a goal of getting in 15 to 30 minutes total for the day when the baby’s about 2 months old.) If you have a mild-tempered baby, this active play time will go swimmingly, and it will go a long way toward helping them learn to sit up. (Editor’s Note: For what it’s worth, both my colicky babies screamed their heads off during tummy time. The exercise wasn’t nearly as cute as it sounded and often didn’t last more than a couple minutes. They still learned to sit, walk and stand on time.) 

What to Do If Your Baby Isn’t Sitting Up Yet

If your baby isn’t making progress toward sitting up during the four- to six-month period, and hasn’t reached the milestone by nine months, it’s a good idea to bring the matter to your pediatrician. Some babies need a little extra help in the form of occupational therapy, but that’s something you should discuss with a doctor who can properly evaluate your child’s motor skill development.

Per the expert, “once your child has mastered sitting up, they’re ready for more mobility [and] you can expect that they will start learning how to crawl, stand, cruise around furniture and walk in no time.” It’s also worth noting that there’s no right or wrong way to crawl and some babies bypass that stage altogether and go straight to cruising. Again, if you have any concerns, your pediatrician is the best person to talk to.