Signs of Autism in Toddlers: A Complete Age-By-Age Checklist for Parents

If your toddler isn’t babbling, pointing, responding to their name, or making eye contact the way other children their age do, you may be noticing early signs of autism spectrum disorder (ASD). The clearest early signs typically appear between 12 and 24 months and include reduced eye contact, not responding to their name, limited pointing or gesturing, delayed speech, and repetitive movements like hand-flapping or rocking. No single sign confirms autism — but a cluster of these signs, especially a loss of skills your child once had, is a strong reason to request a developmental screening right away.

You are not overreacting by researching this. According to the CDC’s most recent surveillance data, about 1 in 31 children (3.2%) in the United States is identified with autism spectrum disorder by age 8, and autism can be reliably diagnosed as early as 18 to 24 months with a structured evaluation. The earlier a child is evaluated, the earlier they can access support — and early support during the toddler years produces measurably better long-term outcomes in communication, learning, and independence.

This guide walks through exactly what to look for at each stage of toddlerhood, what’s typical development versus what warrants a conversation with your pediatrician, the most common mistakes parents make while waiting to act, and what the evaluation and early intervention process actually looks like — including what it looks like here in North Carolina.

What Are the Early Signs of Autism in Toddlers?

Early signs of autism cluster around three areas: social communication, language development, and repetitive or restricted behaviors. A toddler showing several signs across these categories — not just one isolated quirk — is the pattern pediatricians and psychologists look for.

The most commonly reported early signs include:

Little to no eye contact during interactions
Not responding consistently to their own name by 12 months
Limited or absent pointing, waving, or showing objects to others by 12–15 months
Delayed babbling or first words
Preferring to play alone rather than seeking connection
Repetitive movements such as hand-flapping, spinning, or toe-walking
Intense reactions to sounds, textures, lights, or smells
Lining up toys instead of engaging in pretend play
Strong preference for sameness and distress with small changes in routine
Loss of words or social skills the child previously had

A single sign in isolation is common in typically developing children too. What matters clinically is the pattern, persistence, and combination of these signs over time.

Signs of Autism by Age: 12, 18, 24, and 36 Months

Signs at 12 Months

By their first birthday, most children babble with intonation, respond when their name is called, and use simple gestures like waving “bye-bye” or reaching to be picked up. Possible red flags at 12 months include:

No babbling or pointing
No response to their name most of the time
No back-and-forth smiling or gesturing
Little interest in games like peekaboo

Signs at 18 Months

By 18 months, most toddlers say a handful of words, point to show interest, and imitate simple actions. Watch for:

Fewer than 6 words spoken
No pointing to show you something interesting
Not bringing objects to share with a caregiver
Not imitating actions like clapping or waving

Signs at 24 Months

By age 2, most children combine two words (“more juice”), follow simple instructions, and engage in early pretend play. Red flags include:

No meaningful two-word phrases
Little interest in other children
Repeating words or phrases out of context (echolalia)
Lack of pretend play, such as feeding a doll
Strong distress over minor changes in routine

Signs at 36 Months

By age 3, most children speak in short sentences, ask simple questions, and engage in cooperative play. At this age, signs of autism become more distinct and may include:

Limited conversational back-and-forth
Difficulty playing with peers or sharing interests
Very narrow, intense interests
Sensory-seeking or sensory-avoiding behaviors
Repetitive play patterns rather than flexible, imaginative play

If your child was already showing several signs at 12 or 18 months, don’t wait until 36 months to seek an evaluation. Screening and evaluation can begin as early as 12–18 months.

Typical Development vs. Autism Red Flags: Comparison Table

Milestone Area	Typical Development (by 18–24 months)	Possible Autism Red Flag
Eye contact	Makes eye contact during interactions	Rarely makes or sustains eye contact
Name response	Turns/responds when name is called	Doesn’t respond consistently to name
Pointing	Points to show interest (“look at that!”)	Doesn’t point or only points to request items
Speech	Says single words by 12–15 months, phrases by 24 months	No words by 16 months; no two-word phrases by 24 months
Social smiling	Smiles back at caregivers	Limited or delayed social smiling
Play	Engages in pretend play (feeding a doll, “driving” a car)	Lines up toys, spins objects, repetitive play patterns
Imitation	Copies simple actions and sounds	Rarely imitates others
Peer interest	Shows curiosity toward other children	Prefers solitary play, limited interest in peers
Routine changes	Adapts with mild protest	Intense distress over small changes
Sensory response	Typical response to sound/touch/light	Over- or under-reacts to sensory input

Social communication differences are often the earliest and most reliable signs of autism, sometimes visible before language delays become obvious. Watch for reduced eye contact, limited use of gestures, not showing objects to share enjoyment, and difficulty engaging in reciprocal “give and take” interactions like peekaboo or simple games.

A key concept clinicians look for is joint attention — a child’s ability to share focus on an object or event with another person, such as looking at a toy, then looking at you, then back at the toy. Limited joint attention by 12–15 months is one of the most consistently studied early indicators of autism spectrum disorder.

Behavioral and Sensory Signs

Repetitive behaviors and sensory differences are the second major sign category. These can include:

Hand-flapping, rocking, or spinning
Toe-walking
Fixating on parts of objects (like spinning a wheel rather than playing with the whole toy)
Unusual reactions to sound, light, texture, or smell — either extreme sensitivity or seeking out intense sensory input
Strong need for routine and distress when routines change
Very narrow, intense interests for the child’s age

These behaviors are not inherently harmful, and many autistic children use them to self-regulate. Their clinical significance comes from how much they interfere with a child’s ability to explore, play, and connect with others.

Language and Play Signs

Speech delay alone does not mean a child is autistic — many children with pure speech delays catch up with support. What distinguishes autism-related language differences is the pattern:

Echolalia (repeating words, phrases, or lines from shows out of context)
Flat or unusual tone/pitch when speaking
Difficulty using language to request, comment, or share rather than only to get needs met
Loss of words previously used

In play, watch for a strong preference for lining up or sorting toys over imaginative or functional play, and limited interest in playing alongside or with other children.

Developmental Regression: The Sign Parents Often Miss

One of the most important — and most overlooked — signs is regression: a child who was babbling, making eye contact, waving, or saying words, and then stops. Regression most commonly appears between 15 and 24 months and is reported by a meaningful percentage of families of autistic children.

Regression is never something to “wait and see” about. If your child has lost a skill they previously had — a word, a gesture, eye contact, social interest — request a developmental evaluation immediately rather than waiting for the next well-child visit.

Autism in Girls: Why Signs Are Often Missed

Autism is diagnosed roughly 3 to 4 times more often in boys than girls, but research increasingly shows this partly reflects under-identification in girls rather than a true difference in prevalence. Girls with autism are more likely to:

Mask or camouflage social difficulties by mimicking peers
Have special interests that look more “typical” (animals, books, specific characters) and are therefore missed
Show subtler social communication differences that are easy to attribute to shyness

If you sense something is different about your daughter’s social development, even if she doesn’t match the “classic” signs list, it’s worth raising with her pediatrician. Trust your instincts as a parent — you know your child better than any checklist.

Common Mistakes Parents Make When Noticing Signs

Mistake 1: Waiting for the next scheduled pediatrician visit.
You do not need to wait months for a routine appointment. Call and request a developmental screening as soon as you notice concerns.

Mistake 2: Assuming a sign in isolation means autism (or ruling it out because of one “normal” sign).
Autism is diagnosed based on a pattern across multiple areas, evaluated by a trained clinician — not a single behavior.

Mistake 3: Comparing only to one older sibling or one other child.
Development varies. Compare against established milestones (like CDC’s “Learn the Signs. Act Early.” checklists), not just one reference child.

Mistake 4: Believing “boys just talk later.”
Speech delay can be an early sign that deserves evaluation regardless of gender — waiting rarely helps and can delay access to support.

Mistake 5: Choosing “wait and see” after noticing regression.
Loss of previously acquired skills should always prompt prompt evaluation, not a waiting period.

Mistake 6: Assuming an evaluation means a lifelong label with no benefit.
An evaluation provides clarity and access to services, regardless of outcome. Families are never worse off for having accurate information.

What To Do If You Notice These Signs

Write down specific examples. Note what you’ve observed (e.g., “doesn’t respond to name in loud or quiet rooms,” “lost the words ‘mama’ and ‘up’ at 18 months”).
Request a developmental screening from your pediatrician. Ask specifically for an M-CHAT-R (Modified Checklist for Autism in Toddlers) screening — this is a standard, validated 20-question tool used at 18- and 24-month well visits.
Ask for a referral to a comprehensive diagnostic evaluation if the screening flags concerns, or seek one directly — you do not always need a referral to request an evaluation.
Start early intervention services in parallel, if available in your state, while waiting for a full diagnostic evaluation. Early intervention does not require a formal autism diagnosis in most states.
Choose a provider who evaluates children as young as 18 months and can move quickly — evaluation wait times vary enormously between providers, and early access matters.

The Autism Evaluation Process, Step by Step

A comprehensive autism diagnostic evaluation is conducted by a licensed psychologist and typically includes:

Step	What Happens
1. Intake & insurance verification	Paperwork, developmental history forms, and insurance authorization are completed.
2. Parent/caregiver interview	A clinician gathers developmental history, current concerns, and family context — often done virtually.
3. Direct observation (ADOS-2)	A play-based, standardized assessment observes communication, social interaction, and behavior directly with the child.
4. Screening for co-occurring concerns	Many evaluations also screen for ADHD, anxiety, and other developmental differences that commonly co-occur with autism.
5. Results and report	Families receive a full written report and a follow-up session explaining findings, diagnosis (if applicable), and a personalized recommendation for next steps such as ABA therapy or school-based support.

At Little Hearts ABA, this full process — from first contact to results session — typically takes two to four weeks, well under the six-month waitlists many families report encountering elsewhere in North Carolina.

Expert Recommendations for Parents

Trust your observations over reassurance. Pediatricians sometimes offer a “wait and see” approach; if your concerns persist, you have the right to request a referral regardless.
Don’t wait for perfect certainty. You don’t need to be sure your child has autism to request a screening — the screening exists to answer that question.
Track patterns, not single moments. A toddler having an off day is normal. A consistent pattern across weeks and settings (home, daycare, family gatherings) is more clinically meaningful.
Start early intervention immediately if eligible, even before a diagnosis is finalized. Speech therapy, occupational therapy, and developmental support can begin in parallel with the evaluation process in most states.
Choose evidence-based support after diagnosis. Applied Behavior Analysis (ABA) delivered in natural, everyday environments — home, daycare, community — is one of the most researched interventions for building communication, social, and daily living skills in young autistic children.

Statistics Every Parent Should Know

About 1 in 31 children (3.2%) in the U.S. is identified with autism spectrum disorder by age 8, per the CDC’s most recent ADDM Network data.
Autism is about 3.4 times more common in boys (1 in 20) than in girls (1 in 70).
Autism can be reliably diagnosed by age 2 using standardized tools, though the national median age of diagnosis is closer to 47 months — meaning many children wait far longer than necessary.
In North Carolina specifically, the previously reported median age of autism diagnosis was around 36 months, over a year earlier than the national median at the time — reflecting the value of proactive screening in this state.
Roughly 1 in 6 children aged 3–17 has been diagnosed with a developmental disability of some kind, according to CDC parent-reported data.
Early identification and intervention are consistently associated with stronger long-term outcomes in communication, adaptive skills, and school readiness.

Sources: CDC ADDM Network 2022 data, released April 2025; National Institute of Mental Health; Autism Society of North Carolina.

Frequently Asked Questions

What is the earliest age autism signs can appear?

Signs can appear as early as 6 to 12 months, most commonly showing up as reduced eye contact, limited social smiling, and delayed babbling. Most reliable diagnoses are made starting around 18 to 24 months.

Can a toddler show signs of autism and not be autistic?

Yes. Isolated signs, such as a temporary speech delay or a phase of repetitive play, are common in typically developing toddlers. A formal evaluation by a licensed clinician is the only reliable way to distinguish a developmental variation from autism spectrum disorder.

What is the number one early sign of autism?

There isn’t a single defining sign, but reduced or absent response to one’s own name by 12 months, combined with limited eye contact and limited pointing, is one of the most consistently studied early indicators.

Do all autistic toddlers avoid eye contact?

No. Some autistic children make eye contact inconsistently or in atypical ways rather than avoiding it entirely. Eye contact differences are one clue among several, not a standalone diagnostic marker.

Is speech delay always a sign of autism?

No. Many children with isolated speech delays are not autistic and catch up with speech therapy. Autism-related language differences typically appear alongside social communication and behavioral signs, not in isolation.

At what age should I request an autism evaluation?

As soon as you notice a pattern of concerning signs — there is no minimum age requirement. Screenings can begin around 12 to 18 months, and comprehensive diagnostic evaluations are commonly conducted from 18 months onward.

Does my pediatrician have to refer me for an evaluation?

In most cases, a referral from a pediatrician is helpful for insurance purposes, but many diagnostic evaluation providers, including Little Hearts ABA, can also work directly with families to verify insurance and begin the process without requiring you to wait for a referral first.

How long does an autism diagnostic evaluation take?

The full process, from intake to a completed written report, typically takes two to four weeks with a provider that prioritizes fast scheduling, though timelines vary based on insurance authorization and provider availability.

What happens if my toddler is diagnosed with autism?

You’ll receive a full written report explaining the diagnosis, your child’s specific strengths and needs, and personalized recommendations, most commonly including ABA therapy, speech therapy, and/or occupational therapy. A diagnosis opens access to insurance-covered services and early intervention resources.

What if the evaluation shows my child does not have autism?

You’ll still receive valuable information about your child’s developmental profile and any recommended next steps, such as speech or occupational therapy for a different underlying delay. An evaluation is never wasted effort.

Can girls show different autism signs than boys?

Yes. Girls are more likely to mask social differences and have special interests that appear more typical, which often leads to later identification. Persistent parental concern about a daughter’s social development still warrants evaluation.

Is regression always a sign of autism?

Regression — losing a previously acquired skill like a word or gesture — is a significant red flag that should always prompt a prompt evaluation. It occurs in a meaningful subset of autism cases but should never be dismissed as “just a phase.”

Do vaccines cause autism?

No. Numerous large-scale studies involving millions of children, reviewed by the CDC, the American Academy of Pediatrics, and independent researchers worldwide, have found no link between vaccines and autism. Autism has strong genetic and neurodevelopmental origins that begin before or shortly after birth, well before the vaccine schedule.

What is the difference between autism and ADHD in toddlers?

Autism primarily affects social communication and includes repetitive behaviors or restricted interests, while ADHD primarily affects attention, impulse control, and activity level. The two conditions frequently co-occur — an estimated 30 to 40 percent of autistic children also meet criteria for ADHD — so a comprehensive evaluation typically screens for both rather than assuming one explains all the signs.

Can a toddler have autism and still be affectionate or make eye contact sometimes?

Yes. Autism exists on a spectrum, and many autistic toddlers are affectionate with familiar caregivers, laugh, and make eye contact inconsistently rather than never. Autism is ruled in or out based on an overall pattern across development, not the presence or absence of any single warm or connected moment.

Does insurance cover autism evaluations and ABA therapy in North Carolina?

Most private insurance plans and NC Medicaid cover autism diagnostic evaluations and medically necessary ABA therapy following a diagnosis, though coverage details vary by plan. A provider that verifies benefits on your behalf before your appointment can confirm your specific coverage and any out-of-pocket costs in advance.

What should I bring to my toddler’s autism evaluation appointment?

Bring your child’s insurance card, any prior developmental screenings or pediatrician notes, a list of specific examples of the behaviors that concerned you, and any early intervention or speech therapy records if applicable. Video clips of behaviors that are hard to reproduce on demand, like hand-flapping or a lack of response to their name, can also be genuinely helpful for the evaluator.

Conclusion

Noticing possible signs of autism in your toddler can feel overwhelming, but clarity is always better than uncertainty. The signs outlined here — reduced eye contact, limited response to name, delayed or unusual language, repetitive behaviors, and especially any loss of previously acquired skills — are well-established indicators that warrant a conversation with a professional, not a diagnosis in themselves. A licensed clinician using standardized, evidence-based tools is the only way to know for certain, and getting that answer early gives your child the best possible access to support during the years when the brain is most responsive to intervention.

You do not have to figure this out alone, and you do not have to wait months for answers.

If you’ve recognized several of these signs in your toddler, the next right step is a comprehensive autism diagnostic evaluation — not more research, not more waiting. Little Hearts ABA provides evaluations for children 18 months to 18 years, conducted by a licensed psychologist, with insurance verification handled for you and typical turnaround of two to four weeks from first contact to results. Contact our team today to schedule your child’s evaluation and get the clarity — and the plan — your family deserves.