How long does it take to get an autism diagnosis on the NHS?

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If you’ve recently found yourself Googling this question at midnight while eating the kids’ leftover fish fingers… you’re certainly not alone. Many parents reach the point where they recognise their child might be autistic—perhaps because of social differences, sensory needs, or that uncanny ability to remember every single Pokémon ever created—and then discover that getting an assessment is a bit like joining a very long queue for a very slow rollercoaster.

The good news? You can get there.

The slightly-less-good news? The NHS waiting times can vary wildly depending on where you live.

Let’s walk through what to expect, why waiting lists are long, and what you can do in the meantime.

How long are NHS waiting lists for an autism assessment?

The honest answer: anywhere from a few months to several years.

Current NHS data shows that many areas in the UK have waiting lists exceeding 12–24 months, and some regions report waits of 3 years or more. According to recent NHS guidance, services aim to complete a diagnostic assessment within 13 weeks of referral—but in practice, many simply don’t have the staffing or capacity to meet that target (NHS England).

This means two children in two different postcodes can have two very different experiences.

It’s frustrating. It’s exhausting. And it’s absolutely understandable if you’re feeling a bit worn out by the process already.

Why do autism assessment waiting times vary so much?

1. Demand is rising

More families are seeking assessments—which is a good thing, because awareness is higher and stigma is shrinking. But NHS services haven’t always grown at the same pace.

2. Limited specialist teams

Autism assessments require a multidisciplinary approach: doctors, psychologists, speech and language therapists, and specialists trained in tools like the ADOS. These teams are brilliant—but often overstretched.

3. Regional funding differences

Each area allocates resources differently, which means one region might have a well-staffed service, while another is running on optimism and caffeine.​

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What actually happens during an NHS autism assessment?

Although each service does things slightly differently, most follow the NICE guidelines for autism assessment (NICE CG128: Autism in under 19s).

You can generally expect:

• A detailed developmental history (including pregnancy, early milestones, and your child’s current strengths and challenges).

• Observational assessments of communication, interaction, and play.

• Questionnaires or rating scales from parents and school.

• A feedback meeting where you receive the diagnostic conclusions.

This process is thorough and carefully considered—which is wonderful, but also time-intensive.

What can you do while you’re waiting?

Even without a confirmed diagnosis, there’s so much you can do to support your child right now.

1. Share your concerns with school or nursery

You don’t need a diagnosis to get support. Schools can put strategies in place based on your child’s needs today.

2. Learn more about neurodiversity

Trusted resources—like the National Autistic Society (NAS)—offer brilliant parent-friendly information.

3. Try simple home strategies

Think sensory-friendly routines, visual schedules, predictable transitions, and gentle emotional coaching. These help autistic and non-autistic children alike.

4. Consider a private assessment if appropriate

Some families choose a private pathway to reduce waiting time. Reputable clinics (including ours at NeuroDiverseKids.co.uk) follow the same NICE-aligned standards used in NHS assessments.​

Why might a private assessment be quicker?

Private clinics don’t have the same bottlenecks as NHS services, meaning assessments can often be booked within weeks rather than years. For families feeling stuck, this can provide clarity, access to support, and peace of mind much sooner.

Importantly, a private diagnosis should still be based on NICE guidance and be accepted by schools and local authorities—in other words, it’s not a “shortcut,” just a faster route to the same destination.

So… how long does it take?

If you’re going through the NHS, the realistic answer is: longer than any parent wishes, and longer than the NHS intends.

But with the right information, gentle strategies, and a bit of support along the way, your child can still thrive while you wait.

And if you ever need a quicker, clearer pathway, private services like ours are here to help—warm, friendly, and fully aligned with the same high clinical standards.

You’re doing brilliantly, even if it doesn’t always feel like it.

And you’re absolutely not alone in this journey.

​Book an assessment or discuss treatment.