Beyond the debates surrounding the concept of “employability” and the question of how to divide responsibilities between workers and employers, an emerging literature discusses the effect of self-perceived employability on worker behaviour with respect to trade unions. Based on Hirschman’s seminal Exit-Voice-Loyalty model, the present paper aims at contributing to a subject which remains empirically underexplored. Existing research offers no decisive results about the relation between employability and voice behaviours, and it remains unclear about the effects of employability enhancement practices on union constituencies : on the one hand, employability tends to lower the cost of the exit option, and is consequently detrimental to voice ; on the other hand, employability can act as a resource in a power struggle and, as a prerequisite of exit, it makes the voice option less risky or costly, especially when industrial relations take place in a fairly positive climate. In this paper, we propose to go deeper into the examination of this set of relations by introducing a distinction between internal and external employability, and between direct voice and representative, union-mediated voice. To test our hypotheses, we collected data from a survey administered in a French retail bank in 2011. Our findings show that internal employability would favour direct expression to management, with external employability associated with no specific voice behaviour, except when the industrial relation climate is cooperative. This confirms the need for more attention paid to the internal vs external nature of employability. Lastly, our results do not allow us to conclude once and for all that employability is detrimental to unions, and it is not necessarily through their bargaining power and opposition activities that unions are most effective in improving workers position, but through a cooperative attitude with management instead.