This chapter begins by outlining the challenges of preparing a chapter on evidence-based practice (EBP) to underpin the use of music as a therapeutic tool in treatment, in the overall frame of music, health, and wellbeing. It then reviews the terminology of EBP and evidence-based medicine, and discusses autism spectrum disorders and EBP. The chapter concludes that, based on last sixty years of the development of music therapy as a recognized and relevant intervention, there is no doubt that the honeymoon period is over, and EBP is here to stay. Despite examples of attrition in music therapy practice as health, education, and social services tighten their belts and the demand on their resources grows, there is increasing interest in the value of music for health and wellbeing, despite even less ‘hard’ evidence that it is effective against illness and disability.