Early Signs of Autism by Age: A Parent-Friendly Guide

Published September 14, 2026

A calm, practical guide to possible early signs of autism from infancy through preschool, what patterns matter, and when to seek screening or assessment.

Early Signs of Autism by Age: A Parent-Friendly Guide

Parents often notice that something about their child’s communication, play, reactions, or development feels different before they know what it means. Sometimes those differences are related to autism; sometimes they have another explanation.

This guide is not a diagnostic checklist. One sign on its own does not mean that a child is on the autism spectrum, and a child does not need to show every sign. What matters is the overall pattern, how it changes over time, and whether it affects the child’s daily life.

The age ranges below are a guide, not deadlines. Children develop differently, and the same sign may become noticeable at different ages.

Possible signs around 6–12 months

Early differences can be subtle. Parents may notice that their baby:

responds to their name less consistently by around 9 months;
uses fewer facial expressions during social exchanges;
shows less interest in simple back-and-forth games such as peek-a-boo or pat-a-cake;
uses few gestures, such as reaching to be picked up or waving;
looks at people less often or uses eye contact differently.

Any one of these can have several explanations. At this age, it is more useful to notice a pattern over time than to judge one moment or compare one child rigidly with another.

Possible signs around 12–18 months

As communication and shared play develop, parents may notice that their child:

rarely shows or brings objects to share interest;
does not often follow another person’s point or gaze;
does not point to show something interesting by around 18 months;
uses few gestures to communicate;
has limited babbling or spoken words;
does not consistently copy simple actions during play.

Speech delay alone does not identify autism. Hearing, language development, social communication, play, and the child’s overall development all need to be considered.

Possible signs around 18–24 months

Differences may become easier to see as toddlers communicate, play, and handle everyday routines. A child may:

use few gestures or have limited back-and-forth interaction;
repeat words or phrases, sometimes called echolalia;
share enjoyment or interests less often;
play with toys in the same way repeatedly or focus strongly on parts of objects;
rock, spin, flap their hands, or use other repeated movements;
become very distressed by small changes or need routines to stay the same;
react much more or much less than expected to sounds, textures, tastes, smells, light, or touch.

Repeated movement can help a child feel calm or regulated. A focused interest can also be a source of enjoyment and learning. These behaviours become relevant to an autism assessment when they are considered together with the child’s communication, development, and daily needs.

Possible signs around 2–5 years

In the preschool years, parents, caregivers, or educators may notice that a child:

finds it difficult to join other children’s play;
prefers to play alone or has a different way of approaching other children;
has limited flexible pretend play;
finds back-and-forth conversation difficult, even if they have a strong vocabulary;
talks at length about a focused interest but finds conversational turn-taking harder;
uses repeated phrases, an unusual tone, or very literal language;
has a strong need for predictability and finds transitions difficult;
seeks or avoids particular sounds, movements, foods, clothing, lights, or textures;
becomes overwhelmed in busy, noisy, or unpredictable settings.

Signs may not always be obvious

Do not rule out autism because a child makes eye contact, smiles, shows affection, speaks at an expected age, or sometimes uses pretend play. Children on the autism spectrum are different from one another and may show their characteristics in different ways.

Autism can also be missed in girls, verbally able children, and children who copy other children or mask their differences. A child may appear to cope at nursery or school but become exhausted, quiet, anxious, or overwhelmed afterwards. Observations from more than one setting can help show the fuller picture.

Loss of skills needs prompt attention

Speak with a qualified health professional promptly if a child stops using language, social, play, or movement skills they previously used. Loss of skills can have more than one possible explanation and should be assessed rather than assumed to confirm autism.

Monitoring, screening, and assessment are different

Developmental monitoring means noticing how a child’s communication, play, learning, behaviour, and movement develop over time.
Screening uses a structured questionnaire or tool to identify whether closer evaluation may be helpful.
An autism assessment is a fuller professional evaluation that considers developmental history, observations, communication, behaviour, strengths, needs, and possible alternative explanations.

A screening result is not a diagnosis. A negative screen also does not rule out autism when concerns continue.

Screening schedules differ by country. In the United States, the American Academy of Pediatrics recommends general developmental screening at 9, 18, and 30 months and autism-specific screening at 18 and 24 months, as well as whenever a parent or healthcare provider has a concern.

What parents can do next

Write down specific examples. Note what you observed, when it happened, how often it happens, and what helps.
Look across settings. Ask caregivers, nursery staff, or teachers what they notice during play, transitions, communication, and sensory situations.
Bring your concerns to a child-health professional. Depending on where you live, this may be a family doctor, paediatrician, health visitor, nurse, or child-development professional.
Ask directly about developmental screening and assessment. A clear request can be: “I have concerns about my child’s development and would like developmental screening and advice about an autism assessment.”
Ask about support while you wait. Communication, sensory, learning, feeding, sleep, and daily-living needs can still be discussed and supported while an assessment is pending. Availability and eligibility vary by location.

The main message

Noticing differences is not about blaming yourself or labelling a child. It is about understanding what the child may need. Trust persistent concerns, look for patterns rather than one sign, and ask for professional guidance.

Sources and further reading

This article is for general information and is not medical advice. A list or online screening tool cannot diagnose autism. Please speak with a qualified health professional about concerns regarding a child’s development.

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