2 P. ZISS Mateos 2019): to secure residence, increase the ability to travel, to lead family lives across borders, and access economic resources and benefits (Leitner and Ehrkamp 2006; Della Puppa and Sredanovic 2017; Harpaz 2019; Godin and Sigona 2022; Haller and Yanaşmayan 2024). Yet, naturalization decisions are complex, as citi­ zens-to-be contend with oppressive bureaucracy (Haller and Yanaşmayan 2024), feel­ ings of split state loyalties and identities (Sayad 2004), and wider consequences for social networks and families (Godin and Sigona 2022). Moreover, not all ctizenships are alike. It is especially naturalization into ‘higher-tier nationalities’ (Harpaz 2019, 897) that can compensate for a lack of rights through citizenship at birth. This view, however, still assumes a linear hierarchy of citizenship over other statuses that reinforces the imaginary of a clear-cut migrant-citizen binary. This obscures the role of race and class in accessing rights in practice, and how citizenship itself is an institution of social and mobility control that borders, fixes and ‘territorializes’ individuals in place (Malkki 1992; Anderson 2013; De Genova 2018; Sharma 2020). Both together indicate that a more nuanced view of the benefits, costs and choices might be necessary to understand naturalization as a social practice of negotiation between migrants and states. This paper asks how citizenship matters in practice to naturalized and naturalizing migrants, through an exploration of the effects and outcomes of naturalization for Syrian refugees in Turkey. I build on qualitative research with Syrians in Istanbul in 2021, some of whom held temporary protection status while others were naturalized citizens of Turkey. I show that naturalization into higher-tier citizenship was an ambivalent experience that also produced new challenges. For Syrians with citi­ zenship of Turkey, naturalization helped to avoid deportation and arbitrary state vio­ lence, and, for some at least, increased economic security. To access these benefits, however, some lost livelihood and mobility strategies that they adopted not because of their previous, highly precarious status. That is, naturalization contributed to territorial security for naturalized citizens, but also territorialized these new citizens, fixing them onto a territory not of their choice. In deciding where and how to live, Syrians made difficult choices whereby naturalization was not always the best option. The case of nat­ uralized Syrians with citizenship of Turkey challenges received notions of naturalization as formal inclusion, and of the benefits of migrant naturalization as necessarily a better choice compared to both refugee status and irregularity. Instead, I suggest that natural­ ization can have ambivalent benefits and costs for refugees, including simultaneously facilitating and obstructing economic opportunities and spatial mobility, even with a higher-tier citizenship. Citizenship thus overlaps with local and global structures of race, class, and legal status that shape whether and how refugees access formal and equal rights, and whether and how they are able to travel. I argue to view naturalization as a tool of bordering and territorialization in which people are stuck to a certain territory that shapes their mobility in the global world order of nation-states. The paper proceeds as follows: I first outline the debates on the value of citizenship for migrants, showing how current research has underappreciated naturalization’s role in reinforcing conceptions of membership that draw artificial distinctions between migrants and citizens. I then describe citizenship and naturalization practices, and the situation of Syrian refugees, in Turkey, followed by a description of empirical methods. Finally, I discuss how Syrians understand the function of citizenship of Turkey as simultaneously