Early Signs of Autism by Age: What to Watch For (and What to Do)

Nobody knows your child like you do. When something feels different about how they communicate, play, or connect, that feeling deserves attention, not dismissal. Here are the signs clinicians look for at each age, and what typical variation looks like alongside them.

Around 12 months

• Doesn't respond consistently to their name
• Little or no babbling, pointing, waving, or reaching to be picked up
• Limited eye contact during feeding and play
• Doesn't follow your point or look where you look

By 18–24 months

• Few or no single words by 16 months; no two-word phrases by 24 months
• Loss of words or skills they previously had, which is always worth evaluating promptly
• Doesn't bring things to show you or share enjoyment
• Repetitive movements (hand-flapping, spinning, rocking) or intense attachment to specific objects. These are often harmless on their own; see should you stop your child's stimming?
• Strong distress at small changes in routine

Ages 3–5

• Prefers playing alone; limited pretend play
• Difficulty with back-and-forth conversation, even with growing vocabulary
• Repeats phrases or scripts from shows rather than generating language
• Big reactions to sounds, textures, or lights
• Meltdowns around transitions that don't ease with age

School age

• Wants friends but struggles to make or keep them
• Takes language very literally; misses sarcasm and social cues
• Deep, narrow interests that dominate conversation
• Rigid routines; distress when rules or plans change

Girls often show school-age signs more quietly, and they are missed more often as a result. If your daughter wants friends but struggles, holds it together at school and falls apart at home, see our guide to the signs of autism in girls.

What to do next

1. Write down specific examples of what you're seeing.
2. Raise them with your pediatrician and ask directly for an autism evaluation referral.
3. Under 3? Contact early intervention now (Baby Watch in Utah, Infants & Toddlers in Maryland). It's free and doesn't require a diagnosis.
4. Read our step-by-step guide to getting evaluated, or see what support could look like for your child.

The research is unambiguous on one point: earlier is better. Early intervention changes trajectories, and acting on your instinct is never the wrong move.