WHAT IS KNOWN ON THE SUBJECT?: Engagement is regarded as important and beneficial for service users and mental health services A universal definition of engagement is not yet fully agreed upon. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: Based upon their experience, mental health staff use varied engagement approaches to fit with the changeable and unique needs of people who use services (service users). Mental health staff demonstrate qualities such as persistence and adaptability to successfully engage with service users. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Irrespective of professional background, the role of community mental health staff is not restricted to any single approach. Practical help and social support are as seen as important as clinical treatment to establish successful engagement. Little is known about the engagement experiences of mental health staff working in early intervention settings as most studies in this review focused on the perspectives of staff based in assertive outreach or community mental health teams. There is a need to further understand staff experiences of engagement with service users in early intervention settings. Role descriptions and expectations of community mental health workers should account for the wide-ranging flexible approach required in order to deliver appropriate interventions. This may involve a focus on engagement in training programmes. ABSTRACT: Introduction Effective mental health care is dependent on engaging service users, but some individuals do not actively attend appointments, and may stop engaging with mental health services. Quantitative studies reveal some salient factors that seem to predict engagement, but these studies miss the nuances of good clinical practice in this area. A number of qualitative studies of health professionals' experiences and understanding of effective engagement have been published. Aim This review aimed to systematically identify, evaluate and synthesize results from these studies with a view to informing effective practice in this area. Methods Electronic databases MEDLINE, EMBASE, CINAHL, PsychINFO and AMED were searched (PROSPERO systematic review protocol registry (www.crd.york.ac.uk/prospero/; ID CRD42017083976). Of 799 records, ten papers met the inclusion criteria. All papers were subjected to quality appraisal based on the CASP checklist and data systematically extracted. A thematic synthesis of included studies examining mental health practitioners' experiences of engagement in community mental health settings was conducted. Results Mental health practitioners see engaging service users as depending upon complex, multi-dimensional phenomena which should include individualized person-centred approaches as well as practical, social and clinical support. Mental health practitioners demonstrate qualities such as determination and adaptability to establish and maintain engagement with service users. Implications for practice As a core aspect of nurse education, registered mental health nurses and other professionals would benefit from systematic guidance regarding engagement strategies. Most studies in this review focused on assertive outreach or community mental health teams, more clarification is needed of practitioner's engagement experiences in early intervention settings.