The organizational strength of democratic challengers is cited as a key predictor of transitional success. Labor movements constitute a central component of these contentious challengers. In this paper, I utilize event data from both the Egyptian and Tunisian Revolutions (n>8,900) in order to shed light on the divergent mobilization patterns seen in both countries in the aftermath of the uprisings. I combine this analysis with survey data, as well as qualitative evidence derived from newspaper reports and interviews in order to demonstrate the contrasting roles taken up by labor in the post-uprising periods of each country. While labor protest in Egypt remained parochial and epiphenomenal of the the unfolding political process, the Tunisian labor movement constituted a key actor in the transitional process, with mobilization patterns corresponding to their level of influence. This analysis underlines the importance of institutional settings and organizational strength when probing the relationship between protest and regime outcomes.