Physical inactivity is estimated to cost the UK NHS over £1 billion per year. Healthcare practitioners have a key role in supporting increases in physical activity (PA) levels, including referring to exercise referral schemes (ERS). To date, there has been little research into practitioner perspectives on referrals to ERS. To explore the views and experiences of GPs and physiotherapists in relation to factors that influence referral and adherence to ERS. Qualitative study of primary care-based practitioners in Glasgow, UK. Semi-structured interviews were conducted with 14 practitioners (seven GPs and seven physiotherapists). Interviews were recorded and analysed thematically. Four themes are presented. First, healthcare practitioners bring inherent biases to a consultation that impact their approach to PA promotion. Second, clinical time pressures are a major barrier to effective PA promotion. Third, patient-led, compassionate care is the most vital component of behaviour change, with suggestions that promoting peer support and the use of personal anecdotes to normalise vulnerabilities might be helpful. Last, providing ongoing support for change was beneficial to PA promotion. This is often accessed through ERS and is improved by better collaboration between exercise providers and referring practitioners. Practitioners believed ERS referrals could be improved with more targeted training, support for multidisciplinary working, and enhanced communication between the programmes and referrers. Additionally, supporting behaviour change requires time to develop rapport and understand patients' motivations and beliefs. Lack of time is the greatest current barrier to effective PA promotion.