BackgroundThe path of a complaint and patient satisfaction with complaint resolution is often dependent on the responses of healthcare professionals (HCPs). It is therefore important to understand the influences shaping HCP behaviour. This systematic review aimed to (1) identify the key actors, behaviours and factors influencing HCPs’ responses to complaints, and (2) apply behavioural science frameworks to classify these influences and provide recommendations for more effective complaints handling behaviours.MethodsA systematic literature review of UK published and unpublished (so-called grey literature) studies was conducted (PROSPERO registration: CRD42022301980). Five electronic databases [Scopus, MEDLINE/Ovid, Embase, Cumulated Index to Nursing and Allied Health Literature (CINAHL) and Health Management Information Consortium (HMIC)] were searched up to September 2021. Eligibility criteria included studies reporting primary data, conducted in secondary and tertiary care, written in English and published between 2001 and 2021 (studies from primary care, mental health, forensic, paediatric or dental care services were excluded). Extracted data included study characteristics, participant quotations from qualitative studies, results from questionnaire and survey studies, case studies reported in commentaries and descriptions, and summaries of results from reports. Data were synthesized narratively using inductive thematic analysis, followed by deductive mapping to the Theoretical Domains Framework (TDF).ResultsIn all, 22 articles and three reports met the inclusion criteria. A total of 8 actors, 22 behaviours and 24 influences on behaviour were found. Key factors influencing effective handling of complaints included HCPs’ knowledge of procedures, communication skills and training, available time and resources, inherent contradictions within the role, role authority, HCPs’ beliefs about their ability to handle complaints, beliefs about the value of complaints, managerial and peer support and organizational culture and emotions. Themes mapped onto nine TDF domains: knowledge, skills, environmental context and resources, social/professional role and identity, social influences, beliefs about capability, intentions and beliefs about consequences and emotions. Recommendations were generated using the Behaviour Change Wheel approach.ConclusionsThrough the application of behavioural science, we identified a wide range of individual, social/organizational and environmental influences on complaints handling. Our behavioural analysis informed recommendations for future intervention strategies, with particular emphasis on reframing and building on the positive aspects of complaints as an underutilized source of feedback at an individual and organizational level.