Most babies begin to sit up around 4-7 months as their neck, shoulder, back and stomach muscles grow stronger and their head control develops. Tummy time can help prepare your tot for the feat, as can sitting him in your lap (with his head rested against your torso) during storytime.
Your little one will likely topple over often as he perfects his new skill. He might flail his arms with excitement and lose his balance, or he may grow tired of sitting and decide to return to the floor the only way he knows how. Regardless, stay within arm’s reach of him at all times, so you can pad his fall.
Once your kiddo is a master sitter, he’ll likely move on to the next major milestone—crawling! Get a jump-start on baby-proofing if you haven’t already, and prepare for your stationary sweetie to become a go-getter.