Purpose: Agricultural advisory services are perceived by many actors involved in rural development as a key driver behind innovation processes in agriculture. However, changes in national and global contexts cause dramatic changes in the orientation of advisory services, their organisation and their methods of intervention. This article aims to analyse the major research topics related to agricultural advice. Design/methodology/approach: The study is based on an extensive review of literature produced over a ten-year period that is accessible through the CAB, ECONLITandWeb of Science citation indexes. Using keywords related to extension and advisory services, we selected published articles according to the relevance of the results provided in relation to advisory services and the quality of the discussion on past or current controversies. Findings: The results show that the ongoing scientific debates are shaped by the diversity of disciplines, methods, topics and schools of thought. The scientific community largely has focussed on five main themes: (1) the institutional environment of agricultural advisory services; (2) the structures necessary for the operation of an advisory system; (3) the actors providing advisory services and the skills deployed in advisory activities; (4) the approaches, methods, tools and content of advisory activities; and (5) the assessment and impacts of advisory systems. Practical implications: This literature review is useful for researchers and practitioners to better understand research results in the field of advisory services. It paves the way for future research. Originality/Value: Although many articles have been written in recent decades on agricultural advisory services, few studies provide an overview of the contributions of, and debates in, the international scientific community.