Developing autonomous systems that operate successfully in dynamic environments entails many challenges. Researchers introduce the concept of adjustable autonomy to mitigate some of these challenges. Adjustable autonomy enables a system to operate in different autonomic conditions and transfers control between the system’s operators. To gauge the extent to which such autonomy has been studied, this paper presents a systematic literature review of adjustable autonomy. It reviews 171 research papers and examines, in detail, 78 research papers. The review provides a fundamental understanding of adjustable autonomy and its application in multi-agent systems. The paper contributes to (1) identifying adjustable autonomy approaches and evaluating their utility, (2) specifying the requirements of formulating adjustable autonomy, (3) presenting adjustable autonomy assessment techniques, and (4) exploring the adjustable autonomy research and identify the research gaps.