Early Signs of Autism: What to Watch for in Babies as Young as 6 Months

Many parents are surprised to learn that signs of autism can be seen in babies as young as 6 months old. If that feels overwhelming—or even a little scary—you’re not alone. But here’s the hopeful truth: noticing differences early gives you power. It gives you time. And that time? It’s golden for your child’s communication, connection, and development.

This post is about giving you that power—clear, real-life guidance so you know what early social signs to look for, and what they look like in typical development too. You're not expected to know this already. But you deserve to.

A Simple First Step You Can Take Today

Start by watching for social smiling—that moment when your baby smiles in response to you smiling at them, or to playful back-and-forth interaction.

It’s not just any smile. It's a “you smile, I smile” kind of smile. A shared one. An invitation to connect. Social smiling typically begins between 6 to 8 weeks and becomes more consistent around 3 to 6 months.

If you’re not sure whether your baby is doing this or not—that’s okay. It’s really common to miss, especially if you’re not sure what social smiling should look like. Start noticing your baby’s facial expressions during face-to-face time. Are they smiling after you smile? Do they make eye contact and react to your voice or silly sounds with a smile?

Why These Early Signs Matter So Much

The brain is building fast in the first year of life. Connections—and disconnections—start early. Social connection, in particular, is the foundation for everything: language, attention, learning, emotional regulation.

When we notice that a baby isn’t showing typical early social behaviors—like social smiling, eye contact, or responding to name—it may be a clue that their development is taking a different path. That doesn’t mean your child is broken. Not at all.

It means their brain might need different support to build the same foundations. And the earlier we offer that support, the more we can help their brain wire in the skills they need for later.

What to Look For: Key Early Social Signs

Here are some early signs of autism that might show up between 6 to 18 months. These aren’t a diagnosis on their own—but they’re clues worth noticing:

• Lack of social smiling after 2 to 3 months of age
• Limited eye contact during face-to-face interaction
• Not responding to name by 9 to 12 months
• Limited use of gestures like pointing, reaching, or waving
• Not showing you things by holding them up to share, not just hand them to you
• Repetitive movements (rocking, flapping), even in younger babies
• Lack of joint attention—not shifting gaze between you and something interesting

Again, any one of these things on its own doesn’t mean your child is autistic. But several of them together, or something that just feels “off” to you compared to other babies you’ve seen? That’s a signal.

Here’s What These Look Like in Real Life

Let me paint a picture. When my own neurotypical baby was around 7 months old, I could lean in close with a big smile and exaggerated “Hi there!”—and he’d break into a grin right back, just from seeing me happy.

That’s social smiling. Not just a reflex. Not just random. But a shared joy in seeing your face light up.

If a baby looks at you but doesn’t light up in response—or doesn’t look at you much during play—it might be something to explore further. It doesn’t mean they’re not happy. It just means the part of social connection that typically comes online early might be developing differently.

Real-Life Scripts and Interaction Tips

If you're watching for these signs at home, here are a few simple things you can say or do to observe your baby's responses:

• Lean in gently and say, “Hi sweetheart! I see you!” with a big expressive smile. Wait and see—do they look toward you? Smile back?
• Try a peekaboo game: “Where’s mama? There she is!”—and notice: do they anticipate or react?
• Call their name softly from behind or the side. Do they turn toward your voice by 9 months?
• Offer a toy they love, then pause and look at them, as if to say, "Want it?" — do they look at you and reach? Or only grab the toy?

These little moments give you major clues about your baby’s social engagement. Don’t pressure yourself to track everything. Just start noticing.

When to Seek Support

If you’re noticing several of the signs listed above—or if you just feel in your gut like something is different—trust that instinct. You’re not being overprotective. You’re being attuned.

Reach out to your pediatrician or an early intervention provider to share what you’re noticing. A developmental screening can help clarify what’s going on. And if support is needed, you’ll be starting early—while the brain is most flexible and ready to grow new connections.

Want Help Understanding What’s Typical and What’s Not?

I created my free developmental milestones guide to give parents clarity and peace of mind. It walks you through what to look for in key areas like communication, play, and social connection from 6 months through toddlerhood—so you can notice earlier and act sooner, without all the Google spiral.

Need Personalized Support?

If you’d like to talk through your observations with someone who gets both the science and the emotions, you can schedule a free 30-minute discovery call with me to see if consultation is right for you and your family. I’d be honored to support you on this journey.

FAQs About Early Signs of Autism in Babies

Can signs of autism really show up as early as 6 months?

Yes, some early signs—especially in the areas of social engagement and responsiveness—can be seen around 6 months. Things like social smiling, eye contact, and response to your voice are early social milestones that typically appear between 6 to 12 months.

What if my baby doesn’t smile much, but seems content?

It’s absolutely possible to have a quiet, calm baby who isn’t showing strong social behaviors yet. But contentment alone doesn’t rule out early signs. If your baby rarely smiles in response to you or doesn’t seek your face during play, it’s worth watching more closely.

Is it okay to wait and see if my baby grows out of it?

This is such a common impulse—and completely understandable. But waiting sometimes means missing the best window for early support. If something feels off, it’s better to look into it than hope it passes. Early intervention can make a huge difference.

What’s the difference between a 'social smile' and a regular smile?

A social smile is a responsive smile—your baby sees your face, hears your voice, and smiles back. It’s part of a shared interaction, instead of a spontaneous or internal smile. It’s one of the earliest signs of back-and-forth connection.

Where can I learn more about milestones and early signs?

Check out my free developmental milestones guide. It’s designed to help you feel informed and empowered—not overwhelmed.