This doctoral thesis focuses on the relationship between migration experience and formation of political values and attitudes. It seeks to contribute to the literature by unpacking the process of migrant political socialization with an in-depth case study of the Turkish migrants returning from Germany. Its main structure is based on four central arguments in dialogue with the existing political socialization literature: 1) the political socialization is itself a political process, 2) migrant agency in the process of political socialization is understudied, 3) transnational dynamics of migrant political socialization are overlooked, 4) the processual dimension of political socialization is given limited attention. Following these critical points, the thesis seeks to examine the role of migrant agency in migrants’ contact and interaction with German agents of political socialization, identify the process of negative political socialization as an alternative migrant political socialization model, and reveal transnational political socialization trajectories of the migrants. Distinct from the common approaches to migrant political socialization, this thesis relies on an in-depth inquiry through the application of process-oriented methods such as the relational approach and grounded theory methodology to the analysis of the biographical interviews with Turkish returnees from Germany. Focusing on labor and student returnees, as well as the roots migrants, the research seeks to contribute to the literature by capturing a wide array of complexities of the political socialization experience in a time span of almost six decades, extending from pre-migration to post-return. It shows that class, social and cultural capital, transnational conditions, and the political contexts of Turkey and Germany that correspond to the time of migration are among the factors that account for group variations. The group-based approach also defies the tendency to treat the ethnic group as the primary unit of analysis in migration and migrant political socialization studies. Overall, the qualitative nature of the research permits studying the migrants’ own narratives about their everyday experiences. By doing so, it seeks to complement survey research, which works with a number of formal variables for pre-process and post-process dynamics or non-migrant and returnee populations. The analysis shows that in many cases the returnees have not been subject to the conventionally assumed processes of political socialization in Germany because, sometimes for reasons beyond their control, they did not have sufficient contact with the German agents of political socialization, such as the German media, political parties, and electoral campaigns. When there was contact, they often used their agency to strategically filter, ignore and play around these socializers based on their needs and concerns within the power inequalities of the German society. Furthermore, the narratives of the returnees reveal an alternative process of “negative political socialization”. In contrast to the conventional image of migrants’ uncritical embracement of host country values to “fit in”, negative political socialization refers to migrants learning their place as the outsiders of the German polity and their contribution to diffuse system support mechanisms from this position. Lastly, the analysis provides a response to methodological nationalism in political socialization studies, which assumes that the process is contained to the national boundaries of the host and home countries. It reveals that we can differentiate between direct and indirect trajectories of transnational political socialization, in which the migrants’ cross-border ties, identities and practices play a central role. Overall, the findings shed light on the political and processual nature of migrant political socialization, its transnational dynamics, as well as the role of the migrant agency in it.