Ethical behaviour is fundamental to counselling and psychotherapy practice. Two core ethical concepts that transverse all health professions are informed consent for treatment and confidentiality. There are instances where breaches of confidentiality must occur and these need to be clearly articulated to, and be understood, by the client before therapy commences. In counselling and psychotherapy, breaches of confidentiality and the failure to obtain clear consent for therapy are common client complaints. The objective of the current study was to systematically review empirical evidence that examined client understandings of informed consent and/or confidentiality, and to systematically review evidence that examined how therapists obtain informed consent and/or understandings of confidentiality. Academic Search Complete, Informit, PsycARTICLES, Psychology and Behavior Sciences Collection, PsycINFO, and ScienceDirect were searched from January 2007 to May 2017. Studies that contained results relating to client understandings or how therapist obtained informed consent and understandings of confidentiality were included. Seven studies met the inclusion criteria. Client and therapist understandings of confidentiality appear to be context and culture specific. There also appears to be variety in what therapists tell clients that would enable them to give truly informed consent for therapy. No Australian research was located during the search time frame and no studies focused specifically on client understandings or how therapists obtained informed consent and checked for understandings of confidentiality. This neglect suggests research is needed in this area. Whilst the importance of confidentiality and informed consent is widely accepted, actual therapist practice in these areas is unknown.