Many jobs feature tensions between workers’ own motivations, and the objectives imposed on them by management or economic imperatives. We call these tensions ‘meaning of work conflicts’. We ask whether trade unions can intervene in them, or whether they are simply too subjective to be a credible campaigning focus. We examine two professional groups in Britain and France, musicians and healthcare staff. Among musicians, workers tend to negotiate meaning of work conflicts themselves, seeing little role for unions in this process. This engenders legitimacy problems that unions have had to find ways around. By contrast, in the hospitals sector, there is more scope for unions to campaign over the meaning of work, thus potentially increasing legitimacy among staff and the public. The difference is explained by the more diffuse and fragmented nature of employer structures in music, and the more chaotic set of motivations found among music workers.