The purpose of this guidance is to support Scottish education authorities and schools to develop or update local policies and responses to substance use among children and young people in schools. The guidance covers all substances including alcohol, vapes and other nicotine products, and illegal drugs, which will collectively be referred to as ‘substances’ throughout. This guidance is for education authorities, health boards, public schools, school nurses and partners working with schools. Independent and grant-aided schools may also find it of interest. The guidance relates only to substance use by children and young people. Education authorities and schools should have separate policies for responding to substance use by staff, parents or visitors. This guidance does not apply to the lawful use of prescribed medications within schools. The management of prescription medicines are covered in Supporting children and young people with healthcare needs in schools: guidance. This guidance does, however, apply where prescription medications are used by children or young people for whom the medication has not been prescribed. In this guidance, a distinction is made between illegal substances and age-restricted substances. Expectations in this guidance apply to both categories, recognising the differing legal frameworks and potential harms. Education authorities are responsible for ensuring that their policies and practices take full account of the relevant legal requirements. This guidance is non-statutory and aims to support education authorities to make decisions.