Objective: Routine outcome monitoring (ROM) has become an increasingly utilized tool in therapeutic practice that has the potential to improve therapy outcomes. This study aimed to synthesize the findings of existing qualitative studies investigating what facilitates or hinders the implementation of ROM in clinical practice. Method: A systematic search of qualitative studies on clinicians’ experience with the use of ROM in mental health services was conducted via PsycInfo, PsycArticles, Medline, Web of Science, and Scopus databases. Qualitative meta-analysis was used to synthesize the finding of the primary studies. Findings: Fifty-five studies met the inclusion criteria. 22 meta-categories organized into five clusters reflected facilitators and barriers to ROM implementation, namely (1) Clinical relevance, (2) Institutional setting, (3) Practical level, (4) Client variables, and (5) Professional-personal level. Discussion: A meta-analysis showed several spheres that influence the successful use of ROM in clinical practice. Each area includes aspects that therapists perceive as facilitators or barriers to ROM use. The findings of this study can thus serve institutions as well as therapists who are considering the implementation of ROM in clinical practice. Key words: Routine outcome monitoring; qualitative meta-analysis; therapists’ experience; facilitators and barriers to implementation