What drives some Islamists to become “Muslim Democrats,” downplaying religion and accepting secular democracy? This article hypothesizes that one channel of ideological change is migration to secular democracies. Drawing on an ideal point analysis of parliamentary votes from the Tunisian Islamist movement Ennahda, I find that MPs who had lived in secular democracies held more liberal voting records than their counterparts who had lived only in Tunisia. In particular, they were more likely to defend freedom of conscience and to vote against enshrining Islamic law in the constitution. Interviews with several of these MPs demonstrate that they recognize a causal effect of their experiences abroad on their ideologies, and provide support for three distinct mechanisms by which this effect may have occurred: socialization, intergroup contact, and political learning.