Baby developmental milestones: When do babies sit up?

When do babies start to sit up on their own?

Babies start sitting up on their own between 4 and 7 months. Initially, they might need some support, like pillows or sitting in your lap in front of you. Babies learn how to sit unassisted with practice as their muscles strengthen.  

Sitting independently is different from getting into a sitting position on their own. With time and more practice, babies will develop the strength and balance needed to move into a sitting position from lying down. This skill typically develops around 9 months.

Every baby is different and develops at their own pace. Practice tummy time if your baby isn’t showing signs of sitting up. Tummy time strengthens the core, neck, back, and abdominal muscles, which are essential for sitting independently. Here are ways to encourage your baby to learn to sit independently:

• Tummy time: Regular tummy time strengthens the muscles needed for sitting.
• Propped sitting: Use pillows or a nursing pillow to support your baby in a sitting position.
• Playtime: Engage your baby with toys and activities that encourage reaching and balance.
• Gentle pulling: Hold your baby’s hands and gently pull them to a sitting position from lying down. Support their head if needed.
• Mirror play: Babies often enjoy looking at themselves in a baby-safe mirror, which can motivate them to sit up.

Baby gear can be helpful tools for helping babies sit independently, such as Boppy pillows and high chairs. But certain baby gear like exersaucers, bouncers, and infant floor seats (Bumbo seat) can actually impede the development of these skills and should be used sparingly.

Tummy time

Tummy time can start right after birth, even if they are in the NICU or born prematurely. For newborns, aim for 2 to 3 sessions of tummy time per day, lasting about 3 to 5 minutes or until they show signs of fatigue. For older babies, gradually increase tummy time to 15 to 30 minutes daily to help them strengthen their muscles. Tummy time prepares for developmental milestones like sitting up, sitting position, rolling, and crawling

Sitting and crawling–what comes first?

Sitting up usually develops before crawling, since crawling requires significant upper body strength and balance. Babiesbegin crawling between 8 and 10 months. Some babies scoot before they crawl.

Progression to independent sitting

• Head control: Around 2 to 3 months, babies begin to have better control over their head movements.
• Rolling over: By 4 to 5 months, babies can roll from their tummy to their back and vice versa.
• Tummy time: Encourages muscle development in the neck, shoulders, arms, and back.
• Propping up: By 5 to 6 months, babies can prop themselves up on their arms while lying on their stomach.
• Tripod position: Your baby can sit upright while learning forward on their arms and hands for support.

Signs that your baby is ready to sit independently

• Your baby can hold their head in an upright position.
• Your baby can roll over from stomach to back and back to stomach.
• Your baby shows interest in sitting and tries to pull up.
• Your baby reaches for and grabs objects while on their stomach or back.
• Your baby sits in a tripod position.

Safety tips for sitting up

• Always supervise your baby when they are sitting up to prevent falls.
• Ensure your baby sits on a soft, padded surface or play mat.
• Babyproof your home and keep the area free of small objects and sharp edges.
• Use pillows or cushions to provide extra support and prevent toppling over.
• Stay close to catch your baby if they lose their balance.

What should I do if my baby sits up in the crib?

It's common for babies to practice sitting up in their crib. Once they develop this skill, make sure the crib mattress is at the lowest setting for safety. If you notice your baby sitting up during naps or bedtime, gently lay them back down and encourage them to go back to sleep. You might need to do this a few times each night over several days. If your baby can maneuver back down on their own, there's no need to intervene. They will lie back down when they’re ready.

For a smoother bedtime, encourage your baby to practice sitting up and lying down during the day. This will help them master these movements and make it easier when it’s time for bed. Over time, your baby will become more comfortable with lying back down and will return to their normal sleeping positions.

When to see a specialist  

Consult a doctor or a pediatric physical or occupational therapist if your baby isn’t making progress or sitting up by 9 months. Consult your doctor if your baby’s muscles seem stiff or floppy, your baby shows other signs of developmental delays, or consistently favors one side of the body.

If you have any concerns about your baby’s development, reach out to your local or Summer Health pediatrician for additional guidance and support.