Signs of Autism in Toddlers: A Parent’s Age-by-Age Checklist

Quick Answer

If your toddler isn’t babbling back, isn’t responding to their name, or seems to prefer lining up toys over playing with you, you’re not imagining it. The most reliable signs of autism in toddlers fall into three areas: social connection (eye contact, joint attention, responding to their name), communication (babbling, words, gestures), and repetitive or restricted behaviors (lining up objects, hand-flapping, intense focus on parts of toys). No single sign confirms autism spectrum disorder, but a cluster of them, especially a loss of skills your child already had, is worth a same-week conversation with your pediatrician.

How Autism Signs Show Up at Different Ages

Autism doesn’t announce itself with one dramatic symptom. It shows up as a pattern that shifts as your child grows, which is exactly why so many parents second-guess themselves for months before asking for help.

Quick answer: at every age, watch the trajectory of skills, not just a single behavior. A toddler who babbled at 10 months and stopped by 15 months is a bigger red flag than one who was simply always quiet.

Signs of Autism in Toddlers Age 1

Between 9 and 12 months, autism spectrum disorder symptoms are subtle and easy to miss during a 15-minute well-child visit.

• Doesn’t respond to their name by 12 months, even after repeated calls
• Limited or no back-and-forth babbling, cooing, or facial expressions
• Doesn’t point, wave, or reach to be picked up
• Doesn’t follow your gaze or point when you point at something (called “joint attention”)
• Little interest in games like peekaboo or pat-a-cake

In our intake evaluations, this is the age range where parents most often tell us a pediatrician said to wait and see. That’s not always the wrong call; some 12-month-olds are simply late talkers with no autism at all. But it’s exactly why a screening tool, not a gut check, should carry more weight than reassurance alone.

Signs of Autism in Toddlers Age 2

By 24 months, speech delay and social differences become much easier to spot, which is also why age 2 is the peak window for referrals in our clinic.

• Fewer than 50 words, or no two-word phrases (“more juice”)
• Doesn’t imitate others’ actions or words
• Repetitive behaviors: hand-flapping, spinning, rocking, or lining up toys by color or size instead of pretend play
• Strong reactions to sensory sensitivities (certain textures, sounds, or lights causing meltdowns or avoidance)
• Prefers to play alone even when other children are nearby

Age	Typical development	Possible autism sign
12 months	Babbles, waves bye-bye	No babbling, no gestures
18 months	Says 10+ words, points to show interest	Points only to request, not to share
24 months	Combines 2 words, imaginative play emerges	Lines up toys repeatedly, no pretend play

Early Signs of Autism in Toddlers (12 to 18 Months)

This window between the two milestones above is where early intervention has the most research behind it. The single most predictive early sign is a lack of joint attention: your child not looking where you’re pointing, or not bringing you a toy just to share the moment rather than to get something from you.

Other early signs of autism in toddlers to track between 12 and 18 months:

• Regression: losing a word or skill they previously had, at any point
• Unusual eye contact (brief, avoidant, or only during specific activities)
• Fixation on parts of objects, like spinning a wheel, rather than the whole toy
• Delayed or absent pointing to show interest, distinct from pointing to request

Not sure what you’re seeing? Schedule a conversation with our team.

Signs of High-Functioning Autism in Toddlers Age 2 (Often Missed)

This is the group that slips through the cracks most often, and it’s worth its own section because the standard checklists were largely built around more obvious presentations.

A 2-year-old with what’s sometimes called “high-functioning” autism may have age-appropriate or even advanced vocabulary, which throws off parents and providers alike. What gets missed:

• Echolalia: repeating lines from a show, book, or previous conversation verbatim, often in a fitting context, but with little spontaneous conversation of their own
• Strong, narrow interests (letters, numbers, a specific cartoon) pursued with unusual intensity for age 2
• Social interaction that looks fine one-on-one with an adult but breaks down with same-age peers
• Sensory sensitivities to clothing tags, food textures, or loud environments that get labeled “picky” or “strong-willed”
• Difficulty with transitions or changes in routine that seem disproportionate to the situation
• Early signs of masking: copying peers’ expressions or scripts to blend in socially, which can hide underlying differences from anyone not looking closely

In our experience, these toddlers are frequently described by parents as “smart but quirky,” and the diagnosis, when it comes, often lands later than for toddlers with more classic red flags. What we see in practice is that this presentation frequently doesn’t get flagged until preschool or kindergarten, when a teacher notices the social gap between this child and same-age peers in a way a single well-child visit never could.

It’s also worth knowing that autism is not a single, uniform presentation. Two toddlers can both be on the spectrum while one has no words at all and the other has an advanced vocabulary with social and sensory differences instead. The signs above are examples of common patterns, not a fixed checklist every autistic toddler will match.

Does Autism Look Different in Boys and Girls?

Short answer: yes, and it’s a major reason girls tend to be diagnosed later. According to the CDC’s most recent Autism and Developmental Disabilities Monitoring Network data (2022 surveillance data, published April 2025), about 1 in 31 children (3.2 percent) in the United States has been identified with autism spectrum disorder, but that number breaks down very unevenly by sex: roughly 1 in 20 boys compared with 1 in 70 girls.

Part of that gap reflects real differences in presentation, not just how common autism actually is. Girls are more likely to show the masking behaviors described above (mimicking peers, suppressing repetitive movements in public, developing socially “acceptable” scripts), which makes signs of autism in toddlers harder for parents, teachers, and even pediatricians to catch early. If your daughter seems to hold it together at daycare but has meltdowns the moment she gets home, that contrast itself can be a meaningful sign worth mentioning at her next well-child visit, not something to dismiss as end-of-day tiredness alone.

The M-CHAT-R Screening Tool: What It Is and How to Use It

The M-CHAT-R is a free, 20-question parent checklist used to flag toddlers who may need a full autism evaluation. It’s not a diagnosis; it’s a screening step, the same one the American Academy of Pediatrics recommends at the 18-month and 24-month well-child visits.

How it works in practice:

1. A parent answers 20 yes/no questions about everyday behaviors (does your child point, imitate you, respond to their name).
2. Scores fall into low, medium, or high concern.
3. Medium or high scores trigger a structured follow-up interview, then a referral for a full developmental evaluation if concerns persist.

Pediatricians use the M-CHAT-R because it takes under 10 minutes and has been validated across large populations, but a “low concern” score doesn’t rule autism out on its own. It’s one data point, not the final word. You can find the official M-CHAT-R/F screening tool, developed by Robins, Fein, and Barton, at mchatscreen.com. CDC’s Learn the Signs. Act Early. milestone checklists are a useful companion, since they cover the full 2-month-to-5-year range rather than just the autism-specific window. CDC’s autism data and statistics page is the source for the prevalence figures above.

Autism can be reliably diagnosed as early as 18 to 24 months by an experienced clinician, though many children aren’t formally diagnosed until age 3 or later. Earlier diagnosis generally means earlier access to intervention, which is exactly why this two-step approach (screening first, full evaluation second) exists instead of waiting for a single visit to sort everything out.

Is It Autism, a Speech Delay, ADHD, or Something Else?

Short answer: look at whether the social and play differences are there alongside the speech or attention concerns, not just the speech or attention concerns alone. A few common mix-ups worth ruling out before assuming autism or ruling out autism:

• Speech delay alone: a toddler who’s behind on words but still points, makes eye contact, responds to their name, and plays interactively is often dealing with a language-only delay that improves with speech therapy, not autism.
• ADHD-type presentations: toddlers with attention and impulsivity differences can look inattentive or hard to redirect, but they typically still seek out social connection, make eye contact, and engage in pretend play, which is a meaningful difference from the social patterns described above.
• Sensory processing differences without autism: some toddlers are sensitive to textures, sounds, or transitions without the social and communication differences that define autism spectrum disorder.

A pediatrician’s or full evaluation is the only reliable way to sort these apart, since they can and do overlap. That overlap is exactly why a proper screening and evaluation process matters more than trying to self-diagnose from a list like this one.

What to Do If You Notice These Signs

Short answer: don’t wait for certainty, and don’t try to diagnose your own child from a checklist. The path from “I’m noticing something” to “we have a plan” usually looks like this:

1. Write down specific examples. Not “he doesn’t talk much” but “he says 8 words, none in the last month.”
2. Bring it up at, or before, the next well-child visit and ask for the M-CHAT-R directly if it hasn’t been offered.
3. Ask for a referral to a full evaluation if the screening flags concern, rather than accepting a “let’s monitor” plan alone.
4. Start early intervention services in parallel. In Minnesota, you don’t need a formal autism diagnosis to make a referral through Help Me Grow MN (1-866-693-4769), which connects families with speech, occupational therapy, and developmental evaluation through their local school district at no cost.

Early intervention before age 3 has the strongest evidence behind it in the research literature, which is exactly why pediatricians push for a fast referral instead of a wait-and-see approach once red flags appear.

Common misconception: many parents assume they need a diagnosis in hand before any services can start. In practice, most early intervention programs work off a developmental delay finding, not an autism diagnosis, so therapy can often begin months before a full evaluation is complete. If you’re noticing signs of autism in toddlers, don’t let a wait list for diagnosis be the reason your child goes months without speech or occupational therapy support.

It’s also worth knowing what a full evaluation actually involves once you’re referred, since the term “CMDE” trips up a lot of parents on paperwork alone. In Minnesota, a Comprehensive Multi-Disciplinary Evaluation (CMDE) combines a parent interview, direct observation of your child using a standardized play-based assessment, and a written report that determines eligibility and medical necessity for Early Intensive Developmental and Behavioral Intervention (EIDBI) services. Read our full breakdown of what to expect during a CMDE assessment before your first appointment. Most insurance plans that cover autism therapy require this documentation before authorizing services, which is why getting the evaluation scheduled early matters even if you’re fairly confident about what you’re seeing.

If you’re in the Minneapolis area and want a clear next step rather than a long wait list, our team can walk you through what an autism evaluation near you actually involves, from scheduling to what to expect on the day. You can also browse our full range of assessment and therapy services if you’d rather see the whole picture first. Prefer to work through this at your own pace first? Download our printable age-by-age signs checklist and bring it with you to your next well-child visit.

Not sure what you’re seeing? Schedule a conversation with our team.

Conclusion

Noticing these signs doesn’t mean you already have an answer, and it doesn’t mean you’ve done anything wrong as a parent. Autism looks different at every age, from a quiet 12-month-old who isn’t babbling to a talkative 2-year-old whose social differences are easy to miss, and it looks different across children too, including the well-documented gap between how it typically shows up in boys versus girls.

What actually moves things forward isn’t a longer list of symptoms to compare against. It’s a screening tool like the M-CHAT-R, a clear conversation with your pediatrician, and if needed, a referral for a full evaluation. Whatever you find on the other side of that process, you’ll be acting from information instead of guesswork, and that’s what gives early intervention the best chance to work.

You Don’t Have to Figure This Out Alone

Trusting your instincts about your child is hard when everyone around you says, “He’ll grow out of it.”You’ve already done the hardest part just by reading this far and paying close attention.

You don’t need a diagnosis in hand, a completed M-CHAT-R, or a list of perfectly worded examples to reach out. If you’ve noticed signs of autism in toddlers, you just need one honest conversation with someone who does this every day.

Not sure what you’re seeing? Schedule a free 15-minute conversation with our clinical team. We’ll help you make sense of what you’ve noticed and walk you through exactly what a next step would look like, at your pace, with no pressure to commit to anything further.

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