This dissertation is an examination of the relationship between cultural policy and practice among diasporic Iranian communities in the Global North. State-supported multicultural programs aimed at fostering inclusion of immigrants are often criticized for shallow and essentializing displays of culture that constitute what some have called "feel-good multiculturalism." But these programs and the policies that produce them also must be analyzed for what they often produce off-stage, including practices of citizenship, participation, and belonging, both in local communities and across diasporic spaces. In this ethnographic account, I consider diaspora as a category of practice and query the roles of culture and culturalism in relation to multiculturalism policy. The largest or wealthiest Iranian diasporic populations are not found in Stockholm or Toronto, yet these multicultural cities host the biggest Iranian arts festivals in the world. Through comparative ethnographic fieldwork and policy analysis, I examine the national, institutional, and community conditions that have enabled the growth of these large, perennial productions and investigate their impacts on diasporic Iranians. After a brief review of relevant literature and background in Chapter 1, I outline in Chapter 2 the political histories of immigration and multiculturalism in Sweden and Canada to demonstrate the ways in which states and municipal bodies have taken up ideas of culture and belonging in the pursuit of immigrant integration. In Chapters 3 and 4, I analyze the production and after-lives of two large international Iranian arts festivals in Stockholm (Eldfesten) and Toronto (Tirgan) to examine the relationship between them and the proliferation of practices like democratic debate, teamwork, leadership, volunteerism, and cultural, civic, and political activism in these Iranian communities. The link between cultural policy and immigrant participation is not simply the promotion of ethnic art and culture on festival stages; it is a promotion of practice. Using the term practice to mean more than behavior, Iranian diasporic leaders argued that culture is the realm where Iranians should rehearse the skills of democratic life, absent `back home' and yet critical to diasporic practice and a future they envision for Iran. Thus, these citizenization impacts of multiculturalism on immigrant practices are not only evident in Stockholm or Toronto: state-sponsored multicultural programs are also enabling the growth of diasporic citizenship.