When Do Babies Start Smiling

Two different smiles

Almost every parent sees a smile in the first fortnight, and almost every parent is then told it was wind. Both of those are a bit unfair. The AAP's paediatric answer is more careful: "there are some adorable grimaces and grins that parents notice in baby's first month", and "it often seems like the baby is responding to some internal signal, like gas or hunger". Those early grins are real, they are just not the milestone.

The milestone is the social smile: a smile aimed at a person, in response to that person, and repeated. The AAP puts it plainly: "A baby's first social smile usually appears by the end of their second month."

The CDC's revised checklist agrees, listing "smiles when you talk to or smile at her" at two months, and then "smiles on his own to get your attention" at four months — a genuinely different skill, because the baby is now initiating rather than responding. Those ages come from the 2022 revision published in Pediatrics, which set every milestone at the age by which "most (≥75%) children would be expected" to demonstrate it.

The HSE puts the first version at two months: a baby "will smile back at you when you smile at them". At five months, it lists a baby who will "smile spontaneously", and at six months one who will "smile more often – especially at their parents or main caregiver".

Why the social smile is a big deal

Because it is the first two-way conversation. The AAP describes what usually happens next: the baby watches your face, waits for a pause, and smiles the moment you look down — and you smile back. "Her smile caught her parent's attention, and she got a warm smile back in return. In this way, the baby starts to feel good that she knows how to control her own little world in other ways besides crying and fussing."

That loop is the foundation of everything that follows: turn-taking, babbling, gestures, and eventually conversation. The AAP frames the parent's side of it as the point: "When you reliably respond to your baby's cues about when they are ready for play and when they need a break, you let them know that their thoughts and feelings are important."

Smiling past you, not at you

This worries a lot of parents and has a reassuring answer. The AAP addresses it directly: "Some babies may not be ready at first to watch a parent's face for a long time. It may be just too overwhelming for them to look directly into their parent's eyes. By looking just past a parent's face, a baby still is learning about the parent's touch, gentle voice, and facial expressions. With more practice, they will be able to hold their gaze for longer periods."

How to get more of them

Distance and timing do most of the work. Newborn vision is set for about the distance from your face to theirs when feeding, so face-to-face at roughly arm's length is where a baby can actually see you. The HSE's communication advice says the same: "get face to face, make eye contact and smile – a distance of around arm's length allows them to focus on your face."

Then wait. Babies of this age need several seconds to process and respond, and adults tend to move on well before that. The HSE's instruction to "leave little pauses for them to take their turn" applies from the very start.

State matters too. A tired, hungry or overstimulated baby will not smile socially, and a fair test is a calm, alert baby in a quiet room rather than a busy afternoon in a clinic.

If your baby was born early

Use corrected age. A baby born two months early is at two months corrected when they turn four months, and that is the age at which the two-month smile milestone applies to them. The HSE gives the arithmetic in general terms, and the AAP advises adjusting until two years, noting that by then most children born preterm have caught up.

When to raise it

The HSE gives the threshold in its three-month list: contact a GP or public health nurse if your baby "does not smile in response to others". That is the age at which not smiling stops being a range and becomes a conversation.

Its two-month list adds two things that often travel with it: a baby who "does not engage in eye contact when you speak to them" and one who "does not watch and follow you with their eyes". Those are worth raising together, because vision and social response are hard to separate from the outside and a straightforward eye check can settle a lot.

And the instruction that overrides every age: contact a GP or public health nurse if your baby loses a skill they had before. A baby who was smiling socially and has stopped should be reported without waiting for the next review.

One thing worth saying to any parent doing this at three in the morning: how much a baby smiles at you is not a measure of how much they like you, and a baby who is slow to smile is not rejecting anyone. If the waiting is grinding you down, that is worth mentioning at the same appointment.

What comes after the first smile

The smile is the start of a sequence, and the next steps arrive quickly. The CDC's revised checklist lists "chuckles (not yet a full laugh) when you try to make her laugh" and "looks at you, moves, or makes sounds to get or keep your attention" at four months, and "laughs" at six months. The HSE has a baby smiling spontaneously at five months and smiling "more often – especially at their parents or main caregiver" at six.

What that sequence shows is a shift from responding to initiating. A two-month-old smiles because you smiled. A four-month-old smiles to make something happen. That is the same shift that later produces babbling for attention, arms raised to be lifted, and pointing.

Premature babies and the smile that arrives twice

Parents of babies born early often report seeing early grins in the neonatal unit and then waiting what feels like a very long time for a social smile. Corrected age explains most of that: a baby born ten weeks early will usually be around two months corrected, and therefore around four and a half months old, before the social smile is due. The AAP advises adjusting for prematurity until two years, and notes that by then most children born preterm have caught up.