BACKGROUND: There is limited evidence on labour exploitation's impact on migrant health. This population is, however, often employed in manual low-skilled jobs known for poor labour conditions and exploitation risks. The lack of a common conceptualisation of labour exploitation in health research impedes the development of research measuring its effects on migrant health and, ultimately, our understanding of migrants' health needs. AIM: To develop an operational conceptual framework of labour exploitation focusing on migrant workers in manual low-skilled jobs. METHODS: Non-probabilistic sampling was used to recruit multidisciplinary experts on labour exploitation. An online Group Concept Mapping (GCM) was conducted. Experts: 1) generated statements describing the concept 'labour exploitation' focusing on migrants working in manual low-skilled jobs; 2) sorted generated statements into groups reflecting common themes; and 3) rated them according to their importance in characterising a situation as migrant labour exploitation. Multidimensional Scaling and Cluster Analysis were used to produce an operational framework detailing the concept content (dimensions, statements, and corresponding averaged rating). FINDINGS: Thirty-two experts sorted and rated 96 statements according to their relative importance (1 "relatively unimportant" to 5 "extremely important"). The operational framework consists of four key dimensions of migrant labour exploitation, distributed along a continuum of severity revealed by the rating: 'Shelter and personal security' (rating: 4.47); 'Finance and migration' (4.15); 'Health and safety' (3.96); and 'Social and legal protection' (3.71). CONCLUSION: This study is the first to both generate an empirical operational framework of migrant labour exploitation, and demonstrate the existence of a "continuum from decent work to forced labour". The framework content can be operationalised to measure labour exploitation. It paves the way to better understand how different levels of exploitation affect migrant workers' health for global policymakers, health researchers, and professionals working in the field of migrant exploitation.