When Do Babies Sit Up? What You Need To Know

Sitting up is a monumental milestone for babies and their parents. It’s one of the first signs of independence and growing strength. I remember when my babies could finally sit on their own; they were instantly more content, able to look around, observe their surroundings, and use their hands to play.

As one of the earliest gross motor milestones, sitting up is something to celebrate and encourage.¹ You might be eager for your baby to reach this stage, but unsure when to expect it. At what age do babies typically sit up? How can you help them safely practice? And what if your little one isn’t there yet?

This guide answers all those questions, from when babies start sitting up on their own to how to support their progress with confidence.

When Do Babies Sit Up?

So, at what age do babies sit up by themselves? Your baby should be able to sit in a supported seat by 6 months. This may be in a tripod sitting position, in which they hold themselves sitting up by leaning forward on their hands. This could also mean you are supporting them from behind or the sides by holding them up or making sure they do not fall over.²

According to the CDC, your baby should be sitting without support by 9 months. At this age, your baby should also be able to get seated without help.³

In one large study of gross motor development, all the babies achieved sitting without support at around 9 months. The youngest baby to sit without support was just under 4 months old, and the oldest baby to sit was 9 months old. The average age of babies in this study who sat without support was 6 months old.¹

Signs Your Baby Is Almost Ready To Start Sitting Up

Before being able to sit, your baby needs head control and core strength to hold themselves upright. Signs of improving head control and core strength include actions such as:⁴

• Lifting their head during tummy time
• Using arms to hold up their upper body during tummy time
• Rolling over

If your baby has mastered these skills, these may be signs that they are ready to start trying to sit up.

How Do Babies Learn To Sit Up?

Infant strength develops from the top downward, moving from head to feet. The first form of a baby sitting is the tripod sitting position. In this position, their hands prop them up between their outstretched legs.⁴

Eventually, as posture and strength develop, babies learn to sit without the support of their hands, but they are still working on balance and stability. They often need to catch themselves and may still topple over often.⁴

The final stage of sitting is the most stable — at this point, babies can balance even when twisting, turning their head, and moving their arms.⁴ I remember realizing I was no longer worried about my toddler knocking over my baby from a seated position because she had finally mastered balancing while sitting!

How To Help Your Baby Sit Up

Here are some tips and tricks to help your little one practice sitting.

Provide Support

At my daughter’s four-month appointment, since she was rolling and lifting her head in tummy time, our pediatrician encouraged me to help my baby start sitting. She suggested sitting on the floor behind her with my legs in the shape of a V so she was supported from behind and on the sides. I also placed her hands on the floor so she could learn to support herself in the tripod sitting position.

To provide support, you can also place your baby in a seated position and keep your hands around their torso or ribs to hold them up. They will eventually learn to balance with their core or lean on one or both hands while looking around and playing with toys.²

Before my daughter could sit up without support, I used to sit her up with a C-shaped nursing pillow behind her. I would sit across from her or place toys in front of her, encouraging her to play with me while sitting up and balancing. This encouraged her to sit and gave me peace of mind that she would not fall backward and bump her head on the floor.

I suspect, in some ways, this might have backfired. The pillow began to serve as a safety net — she knew it was there and would intentionally throw herself straight backward onto it from a seated position. I am sure she developed core strength from essentially doing sit-ups off the Boppy pillow, but she had to learn the hard way (by falling backward) that the pillow would not always be there once she learned how to sit and balance without support!

Tummy Time

Several studies have demonstrated a positive association between tummy time and faster gross motor development. Babies who practiced more tummy time achieved sitting (both supported and independent), crawling, and pulling to stand at earlier ages.⁵

Exercise and Massage

In cultures that practice infant exercise and massage, babies sit at younger ages on average. Parents are so trusting of their stability that they walk away from their baby when they’re sitting up.⁴

Limit Container Time

While support from parents can help, baby sit-up seats do not help a baby learn to sit independently. It may seem counterintuitive, but these baby containers poorly distribute a baby’s weight and place undue pressure on their back and hips. These seats also restrict a baby’s movements and teach them to rely on the support of these “chairs.” Furthermore, being confined to a baby sit-up seat immobilizes a baby’s joints and prevents their muscles from strengthening.^6,7

Baby Sitting Up: What Milestone Comes Next?

So you have limited your baby’s time in containers, practiced lots of tummy time, provided endless support (literally!), and worked hard to encourage your baby to sit up. Once they have mastered this skill, you probably wonder what might come next. Sitting is usually the next major gross motor milestone after rolling.⁴ It starts the cascade of strength, development, and movement in the first 12 to 18 months of your baby’s life. Once they start sitting, other motor milestones may quickly follow.¹

One study of infant motor development showed that gross motor milestones follow a predictable sequence about 90% of the time. The following milestones to look out for after sitting include:¹

• Crawling on hands and knees
• Standing with support
• Walking with assistance
• Standing independently
• Walking alone

Infant motor milestones after sitting most often occur in the order listed above, but sometimes, crawling and standing with support can be swapped.¹

What To Do if You Suspect a Developmental Delay

If your baby is not meeting these milestones or you are concerned, do not hesitate to ask for help. No one knows your baby better than you! Go with your gut and always seek an exam from a trusted provider if you are concerned your baby may not meet gross motor milestones. If your baby was previously meeting a milestone but stopped performing that action, this is also worth investigating.²

Your pediatrician should be able to perform a developmental screening and refer you to a specialist if needed. It is okay to seek a second opinion if your pediatrician is not concerned, but you are still worried. You can also often make an appointment with an infant physical therapist without a referral from a doctor. Finally, you could call your state’s early intervention program for an evaluation and eligibility. Therapy can make a substantial difference, especially when initiated early.²

My second daughter was on the later end of “normal” for sitting and crawling. Her pediatrician assured me she was not concerned, but gave me a physical therapy referral anyway. She reminded me that I know my baby best. I was not worried she would never meet these milestones; however, I was interested in pursuing therapy to learn how to better help her achieve these goals and catch up to her peers.

In the time leading up to the appointment, we started practicing more supported sitting and motivation through play. Ironically, she started sitting independently and army crawling just days before her physical therapy appointment, so I canceled it. However, I still remember our pediatrician making me feel heard, supported, and validated.

Watching your baby sit up for the first time is a mix of pride and awe. It marks the beginning of new independence, play, and discovery. With your encouragement and support, your little one will soon move from sitting to crawling, standing, and walking — one exciting milestone at a time.

It can be emotional when your baby starts to sit. They suddenly seem a little less like a baby and more like a growing, curious explorer. As bittersweet as it may feel, this milestone opens up a whole new world of play and discovery.

If you’re ever concerned about a developmental delay, your pediatrician is an excellent resource for reassurance and guidance. With your encouragement and support, your baby will be sitting, crawling, standing, and walking—one exciting milestone at a time.