Drawing from a social information processing perspective, we investigate promotive and prohibitive voice as pro-organizational mechanisms mediating the relationship between proactive personality and supervisor-rated promotability. Moreover, we predict that organizational politics and leader-member exchange (LMX) moderate the first and second stages of the mediation processes, respectively. Findings from two multi-wave, multi-source field studies show that 1) proactive personality was positively related to both forms of voice, 2) promotive voice was positively related to promotability and mediated the proactive personality-promotability relationship, 3) the positive relationships between proactive personality and the two forms of voice were stronger when organizational politics were higher, and 4) the positive relationship between promotive voice and promotability was stronger in a low-LMX context. The relationship between prohibitive voice and promotability was nonsignificant in Study 1 but positive in Study 2. The moderating effect of LMX on this relationship was nonsignificant in both studies.