Cognitive behavioural therapy (CBT) is an evidence-based psychotherapy and one of the most widely used treatments for mental health problems. It is generally acknowledged that supervision improves the quality of treatment although systematic descriptions and empirical evaluation of supervision have been sparse. Moreover, there are relatively few valid and reliable instruments to evaluate supervision. Based on a comprehensive review of the supervision literature, six competency domains were identified to cover the scope of CBT supervision: Theory, Focus, Learning strategy, Techniques, Structure, and Interpersonal style. The Moeller, Moerch, Rosenberg Supervision Scale (MMRSS) was developed to evaluate supervisor performance within each of these domains after observation of supervision. The present study examined the psychometric properties of the MMRSS (inter-rater reliability and construct validity), the clinical utility, and satisfaction when using MMRSS to evaluate CBT supervision. CBT supervisors (n = 8) were recruited for the study and provided videos of group supervision. A total of 21 videos were rated using the MMRSS and the Supervisory Competency Scale (SCS) by two independent raters. Supervisees and supervisors completed a satisfaction questionnaire to capture their experience of using the MMRSS during supervision of supervision. The MMRSS showed acceptable internal consistency and validity. Several domains in MMRSS (Structure, Learning strategy, and Interpersonal style) correlated significantly with the corresponding domains in the SCS for cognitive supervision. Preliminary results indicate that the MMRSS may be a valid and clinically useful tool to evaluate CBT supervision, although further systematic evaluation is needed.Key learning aims(1) To understand that empirically founded evaluation of cognitive behavioural supervision is essential for good training.(2) To argue that a modern view of supervision places an emphasis on learning principles.(3) To describe the Moeller, Moerch, Rosenberg Supervision Scale (MMRSS) and the scale’s preliminary psychometric properties.(4) To describe the supervisors’ and supervisees’ reported satisfaction using the MMRSS.