In the past decade, Islamist groups in the Arab world have evolved along sharply different trajectories. After the Arab uprisings of 2011-2012, political openings in a number of countries allowed Islamist groups to play more prominent political roles than ever before. Since that period, however, most Islamist groups have been subject to state repression and political constraints to different degrees. This study assesses the effects of differing Islamist political strategies in response to repressive state constraints across the Arab world. While Islamist groups in some countries, such as Morocco, Tunisia, and Lebanon have survived or even thrived despite state constraints, others, in places such as Egypt, Palestine, and Bahrain have lost political influence. Although the degree of state repression helps to explain part of these diverging outcomes, much of the variation is also explained by strategic interactions between Islamist groups and the state. Islamist groups that actively sought to engage and collaborate with political competitors have managed to maintain significant influence over time, while those that reinforced their ideological or strategic positions in the wake of the Arab uprisings lost significant political influence over time. This study examines recent political decision making by Islamist groups throughout the Arab world to assess the impact of those decisions on subsequent political outcomes using both a comprehensive data set of Islamist political parties, interviews with party leaders, and primary documents associated with party decision making.