<p>The scope of clinical pharmacy practice and research has expanded to encompass behavioural, economic and humanistic dimensions alongside clinical responsibilities. The influence of behaviour on the efficacy of clinical services justifies the application of behaviour change theories to clinical pharmacy and practice research. This facilitates a deeper understanding of human behaviour in relation to health interventions and the provision of clinical pharmacy services. This commentary provides a summary of key concepts that researchers need to consider when using behavioural and/or social theories to underpin their research, outlining: (1) why this is important to support development of the pharmacist’s role in patient care; (2) definitions of theories, models and frameworks; (3) a description of the UK Medical Research Council Framework; (4) an overview of the most commonly used behavioural theories, models and frameworks (supplemented by implementation, communication and other relevant humanistic and social theories); (5) lessons for clinical pharmacy and pharmacy practice researches. The comment aims to assist pharmacy practice and health research colleagues to improve the quality and rigour of theory underpinned research. The guidance in this paper is part of the commitment of the European Society of Clinical Pharmacy to stimulate innovative and high-quality research in all areas of clinical pharmacy.</p>