Summary Musculoskeletal disorders (MSDs) remain a major health problem in industrialized countries. The consequences of work disability represent a heavy burden not only for workers and their families, but also for organizations. While a number of studies on work disability underscore the important role of supervisors in various return-to-work programs, few have focussed specifically on their role, responsibilities, and actions to facilitate the reintegration of workers with work-related musculoskeletal injuries. The general objective of this study was to propose possible courses of action for supervisors during the sustainable return-to-work process of workers with work-related MSDs and to verify their applicability in various organizational contexts and activity sectors in Québec. The specific objectives were to (1) describe the concrete actions taken by supervisors during this process, the different problems they face, and the problem-solving strategies they implement; (2) study the conditions favourable or unfavourable to supervisors’ involvement in work disability prevention; (3) develop possible courses of action for harmonizing supervisors’ role and responsibilities in sustainable RTW with their other roles in the organization (e.g. production, accident prevention) and with the responsibilities of other organizational actors endeavouring to prevent work disability; and (4) verify the pertinence, feasibility, and applicability of these courses of action in various contexts and activity sectors in Québec. A three-phase qualitative sequential design was used to achieve these objectives. For phase 1, a literature review was performed by conducting a systematic search of three specialized data bases. It served to document the international evidence available on the role and responsibilities of supervisors, as well as their involvement in activities essential to the sustainable return-to-work process (objectives 1 and 2 – “international” component). These essential activities were as follows: (1) contacting the absent worker; (2) evaluating the worker and his or her work situation; (3) offering, planning, and implementing the return-to-work (RTW) solution; (4) welcoming the worker back, and implementing and adjusting the RTW solution; (5) doing follow-up of the RTW solution; (6) establishing communication among the actors (e.g. supervisor and worker post-RTW); (7) promoting collaboration within the team and support for the worker; (8) coordinating with the other actors in the RTW process; (9) formalizing policies and procedures; and (10) acquiring knowledge and focussing on experience and skills in order to promote sustainable RTW. Descriptive analyses were performed on the content of the different publications to complete phase 1. For phase 2, a secondary analysis was conducted of data obtained from a Québec case study carried out in four large companies operating in two different activity sectors, in order to describe supervisors’ involvement in these essential activities from the different perspectives present in Québec workplaces: workers, supervisors, managers, and union representatives (objectives 1 and 2 – “Québec context” component). Content analyses of interviews were performed for this component. A synthesis of the results of the first two phases was used to develop possible courses of action and the specific actions associated with them. The essential activities and actions identified in the literature review therefore served as the starting point prior to being adapted in light of the secondary analysis of the workplace interviews (objective 3 – “developing possible courses of action” component). Lastly, phase 3 consisted of verifying the pertinence, feasibility, clarity of wording, and applicability of these four courses of action in various contexts and activity sectors in Québec (objective 4 – “applicability” component). A questionnaire was administered for this purpose. The frequencies of “yes” answers to the various questions were compiled. The suggestions made by the respondents were then re-examined to spark an exchange of ideas among these same actors, both within focus groups and in individual interviews. Content analyses of the participants’ comments for each course of action yielded findings regarding their feasibility and applicability and a proposed operational model for supervisors. Results: For the “international” component (objectives 1 and 2), the literature review yielded 788 references. After eliminating duplications and applying selection criteria, 16 publications were retained. Three publications identified in the reference sections of the selected publications were added to these. Based on the literature review, a total of 10 essential activities and 22 actions for supervisors were associated with the process of sustainable return to work. The literature review also highlighted, on the one hand, the types of problems encountered by supervisors and their problem-solving strategies, and, on the other, the conditions favourable to their involvement in the sustainable return-to-work process. For the “Québec context” component (objectives 1 and 2), as a whole, the concrete actions mentioned by the supervisors in the RTW pertained to the role and responsibilities assigned to them in the organizations and corresponded to the actions identified in the literature review. The actions, problems, and strategies cited concerned, above all, evaluation or planning, notably, information sharing between supervisors and the head of human resources (HR). The supervisors reported having difficulty reconciling their production-related role and responsibilities with those associated with the sustainable return-to-work process. In addition, the supervisors appeared to be more knowledgeable about prevention actions, particularly as regards the documentation of accident circumstances, than they did about actions fostering sustainable reintegration into work. Two types of essential conditions emerged in connection with fulfilling the role and responsibilities of supervisors in the four organizations. The first type concerned the importance of managing interpersonal problems and of supporting the worker, whether in his or her relationships with fellow team members or by ensuring that he or she only does what he or she is capable of doing. This type of condition was mentioned both by the supervisors and the other actors interviewed (manager, human resources advisor, RTW coordinator, worker, and fellow team member). The second type of condition concerned the organizational culture: atmosphere favourable to sustainable return to work, resources, clear and unambiguous procedures regarding the responsibilities of supervisors and other actors, sufficient leeway in choosing and implementing adjustments and accommodations during the RTW, and training (for supervisors and other actors). For example, the supervisors appeared to greatly appreciate having discussion spaces and greater decision latitude for problem solving when it was permitted by the organization. The synthesis of the essential activities and concrete actions identified in the literature review and the results of the secondary data analysis pointed to eight courses of action and 23 specific actions (objective 3). For the “applicability” component (objective 4), 19 participants (4 supervisors and 15 other actors) from 19 Québec organizations operating in six different activity sectors completed the questionnaire. Eleven of them (1 supervisor and 10 other actors) also participated in the focus group. Generally speaking, the 19 respondents found that the courses of action were pertinent, formulated appropriately and exhaustively, and applicable in favourable organizational contexts in Québec. These favourable contexts concerned formalization of the role and responsibilities of supervisors regarding sustainable return to work, organizational culture, organizational resources, decision latitude given to supervisors in making temporary modifications to the organization of work, and the possibility of training for supervisors on the actions requested in the context of the worker’s reintegration. The comments obtained also revealed specific aspects of applicability related to characteristics inherent to the organizations: size, location, union presence or not, prevalence of sick leave cases, and nature of the work. This study resulted in a clearer identification of the role and responsibilities of supervisors regarding the sustainable return-to-work process in various organizational contexts in Québec. In particular, it described in detail the actions taken by supervisors, the problems they encountered, and the strategies they used to overcome these problems, as well as the conditions favourable to their involvement in the process. The study also led to the formulation of four possible courses of action for implementation in organizations and by supervisors themselves to promote the sustainable return to work of workers with work-related MSDs. The participants considered these courses of action to be pertinent, feasible, and applicable. After drawing up a list of findings regarding the need to clarify the differences between the supervisor’s role and that of other actors in the sustainable return-to-work process and regarding the pertinence and feasibility of the courses of action, two recommendations were put forward for the organizations. An operational model was proposed to guide the harmonization – in the context of formalizing procedures to support sustainable return to work – of the role and responsibilities of supervisors with those of the other actors in the process.