The term consultancy is used in many contexts. It has been applied to advanced nursing practice roles such as clinical nurse specialist, advanced nurse practitioner, nurse practitioner and other occupations. This causes confusion in the healthcare setting as the word is often used interchangeably between roles and has traditionally been used in a medical context. In addition, the development of nurse consultant posts has further compounded the uncertainty around consultancy. However, regardless of the role holder, consultancy in nursing is normally used in the context of a person in possession of expertise. This article describes consultancy in nursing; identifying its development, approaches, application and possibilities for the future.