Purpose: To advance the quality of mental healthcare in Europe by developing guidance on implementing quality assurance. Methods: We performed a systematic literature search on quality assurance in mental healthcare and the 522 retrieved documents were evaluated by two independent reviewers (B.J. and J.Z.). Based on these evaluations, evidence tables were generated. As it was found that these did not cover all areas of mental healthcare, supplementary hand searches were performed for selected additional areas. Based on these findings, fifteen graded recommendations were developed and consented by the authors. Review by the EPA Guidance Committee and EPA Board led to two additional recommendations (on immigrant mental healthcare and parity of mental and physical healthcare funding). Results: Although quality assurance (measures to keep a certain degree of quality), quality control and monitoring (applying quality indicators to the current degree of quality), and quality management (coordinated measures and activities with regard to quality) are conceptually distinct, in practice they are frequently used as if identical and hardly separable. There is a dearth of controlled trials addressing ways to optimize quality assurance in mental healthcare. Altogether, seventeen recommendations were developed addressing a range of aspects of quality assurance in mental healthcare, which appear usable across Europe. These were divided into recommendations about structures, processes and outcomes. Each recommendation was assigned to a hierarchical level of analysis (macro-, meso- and micro-level). Discussion: There was a lack of evidence retrievable by a systematic literature search about quality assurance of mental healthcare. Therefore, only after further topics and search had been added it was possible to develop recommendations with mostly medium evidence levels. Conclusion: Evidence-based graded recommendations for quality assurance in mental healthcare were developed which should next be implemented and evaluated for feasibility and validity in some European countries. Due to the small evidence base identified corresponding to the practical obscurity of the concept and methods, a European research initiative is called for by the stakeholders represented in this Guidance to improve the educational, methodological and empirical basis for a future broad implementation of measures for quality assurance in European mental healthcare.