This study uses data from the recent Australian Workplace Industrial Relations Survey to test the union voice hypothesis that unions reduce quits. Unlike the U.S., however, it is argued that union voice may not be directly correlated with union membership as a result o the protections afforded trade unions by the unique Australian industrial relations system. It is found that, while unions are inversely associated with quit rates, this effect is strongest where union membership is supplemented with a more direct indicator of what unions actually do in the workplace.