How does the family influence citizens’ political ideology, and what role do family dynamics and structure play in this process of political socialization? As society and family forms are changing, this study provides new insights in political socialization research by investigating how gender dynamics in the family, parental separation, and intergenerational social mobility affect the transmission and development of citizens’ political ideology in multiparty systems in Europe. The German Socioeconomic Panel and the Swiss Household Panel are the most important data sources. The first empirical chapter provides a descriptive account of the level of transmission of left–right ideology, showing a large and stable influence of the parental on the child’s ideology. Especially the similarity of parental ideology favours this process. Chapter 3 addresses gender effects in political socialization, showing that the political ideology of both parents equally influences the ideology of their children, irrespective of their gender. In Switzerland, moderate left-wing effects of the presence of an older sister are found for females, and in families of a centrist ideology. For males, however, having a female eldest sibling has a right-wing effect. Chapter 4 investigates the ideological consequences of parental divorce, showing with pan-European data that adults whose parents separated during childhood hold a more leftist ideology. Longitudinal analysis using Swiss data shows that this is partially caused by the mother becoming more leftwing after separation from the partner. Finally, Chapter 5 addresses how vertical and horizontal intergenerational social mobility affect the ideological transmission process from parents to children, showing that especially the upwardly mobile are less influenced by the parental ideology. However, it is demonstrated that self-selection into social mobility plays an important role herein. The overall conclusion is that the family is important in shaping voters’ political ideology until in adulthood, not only in terms of intergenerational transmission, but also in terms of direct effects of family experiences and structure.