How to Know If Your Toddler Shows Signs of Autism

Early signs of autism in toddlers most commonly involve differences in communication, social interaction, and repetitive or restricted behavior. These signs can appear as early as twelve months and tend to become more visible between eighteen and twenty-four months. A consistent pattern across multiple areas — rather than a single sign in isolation — is what warrants a professional assessment. Ontario families do not need to wait for a diagnosis to begin a developmental assessment or access early support.

Key takeaways:

Key signs to watch for include not responding to name, limited pointing or gesturing, speech delays, reduced eye contact, repetitive behaviors, and difficulty with transitions
Developmental regression — losing skills a child previously had — warrants prompt attention rather than a wait-and-see approach
The M-CHAT-R/F screening is administered at eighteen- and twenty-four-month check-ups in Ontario; a positive screen leads to referral for full assessment, not a diagnosis

If you’re reading this, something has probably caught your attention. Maybe your toddler isn’t responding to their name the way you expected. Maybe a family member said something after a recent visit. Maybe your child’s development feels a little different from their peers, and you’re not quite sure what to make of it — or whether you’re overreacting, or missing something important.

That combination of concern and uncertainty is one of the most common things parents describe when they first come to us. And the fact that you’re paying close attention is already the most important thing you can do.

This article walks through the early signs of autism that tend to appear in the toddler years, organized by age so you have a clear picture of what’s typically expected at each stage and what patterns are worth discussing with a professional. It won’t diagnose your child — only a qualified clinician can do that — but it will help you understand what you’re seeing, what it may or may not mean, and what to do with that information.

One Thing to Hold Onto Before You Read the Signs

Every sign described in this article can appear in toddlers who do not have autism. Children develop at enormously varied paces, and many behaviors associated with autism — preferring solo play, becoming distressed by routine changes, slow speech development — are also common in typical development at certain ages or in certain temperaments.

What tends to matter most is not any single sign, but a pattern: whether the same behaviors show up consistently, across different settings, with different people, and over a period of time. A toddler who occasionally doesn’t respond to their name when absorbed in play is likely not showing a sign of autism. A toddler who consistently does not respond to their name in quiet, one-on-one situations, across many different weeks, alongside other changes in communication or social interest — that pattern is worth discussing with a professional.

Read what follows with that in mind. The goal is not to find a match and reach for a conclusion, but to build a picture that helps you have an informed, specific conversation with a pediatrician or developmental specialist.

Signs to Watch For Around 12 Months

The first year of life is when some of the earliest signs of autism can begin to emerge — though they are often subtle and easy to attribute to individual variation at this age. By around twelve months, most children are consistently doing the following:

Responding to their name when called in a quiet setting
Making eye contact and using it to share interest or excitement with a caregiver — looking at you and then at something they find interesting, then back at you
Pointing or reaching to show things, not just to ask for them
Waving, clapping, or using other simple gestures
Babbling back and forth with a caregiver in a conversational rhythm
Imitating simple sounds and facial expressions
Turning toward familiar voices

Signs that may be worth discussing with a pediatrician around twelve months include:

Not responding consistently to their name by twelve months, even in a quiet room with no distractions
Limited or absent pointing, reaching to show, or waving gestures
Little or no back-and-forth babbling with a caregiver
Limited eye contact, particularly during feeding or face-to-face interaction
Seeming uninterested in people’s faces or voices in a way that feels different from other children their age
Not following when a caregiver points toward something to look at together

At twelve months, individual variation is wide and a single observation rarely tells the whole story. What matters is whether these patterns are consistent over time and whether they appear alongside other signs.

Signs to Watch For Between 12 and 18 Months

This is the window when differences in communication and social development become more consistently visible for many children. It is also the age at which the American Academy of Pediatrics recommends formal developmental screening — and when Ontario’s M-CHAT-R/F screening is typically first administered.

Communication and language

Fewer words than expected — most children have at least one or two clear, intentional words by around twelve to sixteen months
Not using gestures alongside speech attempts, or relying entirely on pulling a caregiver’s hand rather than pointing or showing
Difficulty with joint attention — looking at an object and then at a parent to share interest in it, rather than just to get something
Appearing to hear well in general but not reliably responding to their name or simple verbal prompts

Social interaction

Limited interest in other children or in watching what other children are doing
Not imitating actions or facial expressions observed in others
Fewer social smiles in direct response to another person’s smile
Seeming more comfortable engaging with objects than with people

Behavior and sensory experience

Strong, consistent reactions to specific sounds, textures, lights, or physical sensations — either highly sensitive or appearing not to notice things that would bother most children
Repetitive body movements that appear frequently and seem self-directed, such as rocking, hand-flapping, or spinning
Intense attachment to specific objects or strong distress when familiar routines are changed
Unusual ways of exploring objects — looking at them from unusual angles, focusing on one part of a toy rather than the whole thing

Signs to Watch For Between 18 and 24 Months

By eighteen months, most children have a growing and actively used vocabulary, are showing clear interest in other people, and are beginning to engage in simple pretend play. This is the age when the gap between what is typical and what some children with autism are doing often becomes more clearly visible. The M-CHAT-R/F screening is also recommended at the twenty-four-month check-up.

Language and communication

Fewer than fifteen words by eighteen months, or fewer than fifty words and no two-word combinations by twenty-four months
Repeating words, phrases, or entire sentences heard from adults or media without apparent communicative intent — this is called echolalia and is a common pattern in autism
Using language primarily or only to request things, but rarely or never to comment, share an observation, or connect with another person
Difficulty following even simple two-step instructions

Social play and interaction

Limited or absent pretend play — not feeding a stuffed animal, not using objects symbolically in play, not acting out simple everyday scenarios
Difficulty taking turns, even in very simple games
Appearing unaware of or indifferent to other children
Struggling to read other people’s facial expressions or emotional states
Preferring to play alone and showing little interest in initiating or joining interaction

Developmental regression — an important sign to take seriously

Some children who appear to be developing typically begin to lose skills they previously had — words they were using, social behaviors they had developed, or responses they reliably showed. This regression most commonly occurs between fifteen and twenty-four months and is considered one of the most significant early indicators of autism. If your child has lost language or social skills they previously demonstrated — even partially, and even gradually — do not wait for the next scheduled appointment. Contact your pediatrician directly, explain what you’ve noticed, and ask for an urgent referral.

A Note on Girls and Less Obvious Presentations

Autism is diagnosed significantly more often in boys than in girls. Research increasingly suggests this reflects diagnostic bias at least as much as actual differences in prevalence — girls with autism often present quite differently from the profile most people associate with the condition.

Girls on the autism spectrum may make eye contact more readily, mask social difficulties through imitation and learned social scripts, appear more engaged in social settings, and adapt well enough in structured environments that their differences go unnoticed by professionals and family members. Their challenges often emerge more visibly as social demands increase — in later childhood or adolescence — rather than in the toddler years.

If you are the parent of a girl and something about her development feels different even though she appears socially engaged, that instinct is worth following up. The signs of autism in girls can be subtler and are more frequently missed at early ages. A developmental assessment is the appropriate response to a persistent, specific parental concern regardless of how a child presents on the surface.

What These Signs Do Not Mean

Finding several of these signs familiar does not mean your child has autism. It means your observations are worth sharing with a qualified professional who can place them in the full context of your child’s development.

Many of the signs above also appear in children with:

Speech or language delays without autism
Hearing difficulties — which is why a hearing test is typically one of the first referrals made when speech or communication concerns arise
Anxiety or highly sensitive temperament
Sensory processing differences that are not part of autism
Other developmental differences that are distinct from ASD

A thorough assessment — not a checklist, not an article, not a comparison with other children at playgroup — is what produces a meaningful clinical picture. The role of this article is to help you decide whether that assessment is warranted. For most parents who are noticing a persistent pattern across several of the areas described above, the answer is yes.

What to Do If You’re Noticing These Signs

If several of these patterns feel consistently familiar, here is a practical and realistic pathway forward for families in Ontario and the GTA.

Talk to your child’s pediatrician specifically and soon

Share what you have observed with as much detail as possible — what you’re noticing, when you started noticing it, how consistent it is, and in what situations it appears. Vague expressions of general concern are harder for a pediatrician to act on than specific observations. Ask explicitly for a referral to a developmental paediatrician if your concerns are not fully addressed at the visit. Also ask for a hearing test if speech or communication is part of your concern — hearing difficulties should be ruled out early.

Request a behavioral assessment at a pediatric clinic

You do not need a pediatrician’s referral or a confirmed diagnosis to begin a behavioral assessment at a clinic like SenseBloom. A Board Certified Behaviour Analyst (BCBA) can assess your child’s current developmental profile — their communication, social skills, behavioral patterns, and daily routines — and give you clinically grounded information about what your child needs right now. This process can begin in parallel with the medical diagnostic pathway, so you are not waiting on two separate queues before any support begins.

Register with the Ontario Autism Program (OAP) early if appropriate

If your child has received or is likely to receive an autism diagnosis, registering with the OAP as early as possible is important because wait times for funded services can be significant. Your therapy provider or pediatrician can help guide you through this process. Registration does not commit you to anything; it starts the clock.

Consider beginning early intervention support now

Early intervention through ABA therapy can begin before a formal diagnosis is confirmed. If you are wondering why early timing matters, our article on early intervention for autism explains what that support looks like in practice and why the developmental window your toddler is in right now is significant. For children who are also showing communication delays specifically, speech therapy alongside ABA is often recommended from the outset.

If You’re Reading This and Wondering Whether You Waited Too Long

Parents who notice signs in retrospect — or who have been reassured to “wait and see” for longer than felt right — sometimes arrive at this point carrying a layer of guilt alongside their concern. That is worth naming honestly: the fact that you are here now, seeking information and next steps, is what matters.

There is no developmental window that closes entirely. Children who begin assessment and support at two, three, or four years old make meaningful progress. The earlier a child begins support, the more time they have to build skills before school age — but a later start is not the same as no chance. You have not run out of time.

How SenseBloom Supports Families Across the GTA

SenseBloom is a pediatric therapy clinic with locations in North York and Ajax, supporting families across the Greater Toronto Area. We work with toddlers and young children whose families have noticed signs of concern — with or without a formal diagnosis in place — providing individualized assessments and therapy programs built around each child’s specific strengths and needs.

As a trusted provider of ABA therapy in Toronto and across the GTA, we offer a free consultation for families who are at the stage of figuring out what their child needs. No diagnosis is required and there is no pressure to commit to anything before you have had a chance to talk things through with a member of our clinical team.

Frequently Asked Questions

Can autism be diagnosed in a toddler under two years old? A formal diagnosis of autism can be made as early as eighteen months in some cases, though many children are not diagnosed until later because the signs can be subtle or inconsistent in early toddlerhood. If you have concerns about your child before eighteen months, sharing those concerns with your pediatrician is still the right step — early referral for assessment is always appropriate when concerns exist, regardless of age.

My toddler only shows one or two of these signs. Should I be worried? One or two signs in isolation, without a consistent pattern across different settings and over time, may not indicate autism. However, any persistent concern about your child’s development is worth discussing with a pediatrician or developmental specialist. You know your child better than anyone — your observations are valid clinical information, and a professional can help you understand what they mean in context.

What is the M-CHAT-R/F and when does my child receive it in Ontario? The Modified Checklist for Autism in Toddlers, Revised with Follow-Up (M-CHAT-R/F) is a validated screening questionnaire typically completed by parents at the eighteen- and twenty-four-month well-child visits. A positive screen does not mean your child has autism — it means a referral for a more thorough developmental evaluation is recommended. If you are concerned before these scheduled visits, you can ask your pediatrician to administer the screening earlier.

What is the difference between an autism screening and a full developmental assessment? A screening is a brief, standardized tool used to identify children who may benefit from further evaluation. It is not diagnostic. A full developmental assessment — conducted by a developmental paediatrician, psychologist, or multidisciplinary team — is what leads to a formal diagnosis. A behavioral assessment at a therapy clinic like SenseBloom evaluates a child’s developmental profile and informs therapy planning independently of a medical diagnosis.

My toddler was developing typically and has started losing skills they previously had. What should I do? Developmental regression — losing skills a child previously demonstrated — is a sign that warrants prompt professional attention rather than a wait-and-see period. Contact your pediatrician directly rather than waiting for the next scheduled visit. Describe specifically what skills have been lost, when you first noticed the change, and whether the loss has been gradual or sudden. This information will help your pediatrician determine the urgency and type of referral needed.

Do I need a diagnosis before starting ABA therapy or a behavioral assessment? No. At SenseBloom, a behavioral assessment can begin before a formal diagnosis is in place. Many families start the assessment and therapy process while the medical diagnostic pathway is still underway. A diagnosis is required for Ontario Autism Program (OAP) funding, but it is not required to begin working with our clinical team or to access a free initial consultation.

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This article is intended for general informational purposes only and is not a substitute for professional medical or clinical evaluation. If you have concerns about your child’s development, please consult a qualified healthcare provider or developmental specialist. Reviewed by Yasamin Yousefi, SenseBloom Therapy & Development.

Sense Bloom Therapy