Under what circumstances do voters prefer Islamist political parties to other political parties? In multiple elections over the past decade in both Tunisia and Morocco, Islamically-oriented parties have competed against a wide range of other parties. In some, but not all, of these elections, the party with the strongest identifiable Islamic identity has emerged as the party with the most votes (Ennahda in Tunisia and the PJD in Morocco). Using both qualitative and quantitative analysis this paper examines the individual correlates of voting for Islamist parties and tests three main hypotheses: 1) Islamist parties are punished by voters when they are perceived to be ineffective on economic promises; 2) Islamist parties are supported when they are perceived to be more collaborative with other parties; and 3) Islamist parties are supported when they are perceived to be more identifiably Islamic in orientation. These hypotheses are tested through two separate online surveys in Tunisia and Morocco, and by using existing data from recent public opinion surveys. The unique surveys utilized in this paper assess voters' comparative evaluation of competing parties and include survey experiments that prime respondents to think about a specific statement made by the relevant Islamist party. Initial research to date suggests that voters are likely to see Islamist parties as unreliable in economic promises over time but are more willing to vote for Islamist parties when they are seen as collaborative with other parties. These effects are stronger in Tunisia than in Morocco, in part due to the competitive political framework in Tunisia and lower influence on policy outcomes from unelected actors.