Confidentiality of client communications is one of the ethical foundations of the social work profession and has become a legal obligation in most states. Many problems arise in the application of the principles of confidentiality and privilege to the professional services provided by social workers. This entry discusses the concepts of client confidentiality and privileged communications and outlines some of the applicable exceptions. While the general concept of confidentiality applies in many interactions between social workers and clients, the application of confidentiality and privilege laws are particularly key to the practice of clinical social workers in various practice settings.