The National Institute for Health and Care Excellence (NICE) Guidelines on Autism consist of three publications Autism: recognition, referral and diagnosis of children and young people on the autism spectrum (NICE clinical guideline 128), Autism: recognition, referral, diagnosis and management of adults on the autism spectrum (NICE clinical guideline 142) and Autism: the management and support of children and young people on the autism spectrum (clinical guideline 170 published in 2013). As a suite of guidelines with associated information, including audit tools and pathways, the intention is to promote guidance for a seamless service across the life span. Autism is the term used in the guidelines to encompass all diagnoses of ‘pervasive developmental disorder/autism spectrum disorder’ and subgroups as in recent Department of Health, National Audit Office and Public Accounts Committee documents. The guidelines draw together systematic reviews and expert opinion to produce clinical practice recommendations covering recognition, referral, diagnosis, interventions, both psychosocial and pharmacological, as well as organisation of services for children, young people and adults. This article summarises the key practice recommendations, highlights where gaps remain in the evidence base and describes some of the challenges for implementing the guidelines in routine clinical practice.