Drawing hypotheses from resource mobilization and resource partitioning theories (RMT and RPT), this article examines how interorganizational competition and social movement industry (SMI) concentration affect the level of tactical and goal specialization of protest organizations associated with the peace, women's, and environmental movements. Additionally, the article examines how specialization affects the survival of these organizations. By and large, the findings are commensurate with the expectations of RMT and RPT. Results indicate that interorganizational competition leads to more specialized tactical and goal repertoires. Concentration in the SMI also leads to specialization, but this is only true for less established organizations. Results also indicate that tactical and goal specialization decrease organizational survival, unless the industry is highly concentrated.