Selective mutism (SM) is a condition where children are able to talk comfortably in some situations such as at home or around familiar relatives, but are not able to use their voice in other social situations where there is an expectation for speaking such as at school or with less familiar people. SM is a form of social anxiety where the child fears that when people hear their voice they will react in a way that might be embarrassing for them or that they may be judged for how they sound or what they say. This fear prevents the child from being able to speak freely. Sometimes children with SM are unable to speak to any adults or peers at school and go for the entire school day without talking. Sometimes they can speak to select people (e.g., 1 or 2 peers but not their teacher, or they speak to adults but not peers), and sometimes children are able to whisper to a large number of people but unable to use their voice. Although Selective mutism usually appears around three years of age, it is often not diagnosed until much later (e.g., early to mid primary school). The delayed referrals to treatment is often due to the belief that the child will ‘grow out of it’ and eventually start talking. However, this is often not the case, as improvements tend to occur very slowly (if at all) if it is left untreated and children tend to still experience anxiety. Early childhood workers and speech therapists play a key role in early detection of the condition and in ensuring that steps are taken before the mutism becomes more habitual. In the past ten years or so, the recognition that selective mutism is a form of social anxiety has led to the development of effective treatment programs, such as cognitive-behaviour therapy (CBT). CBT programs aim to gradually practice ‘brave talking’ in social situations, including school and preschool.