In this monograph, we argue for the establishment of a developmental science of politics that describes, explains, and predicts the formation and change of individuals' political knowledge, attitudes, and behavior beginning in childhood and continuing across the life course. Reflecting our goal of contributing both theoretical conceptualizations and empirical data, we have organized the monograph into two broad sections. In the first section, we outline theoretical contributions that the study of politics may make to developmental science and provide practical reasons that empirical research in the domain of politics is important (e.g., for identifying ways to improve civics education and for encouraging higher voting rates among young adults). We also review major historical approaches to the study of political development and provide an integrative theoretical framework to ground future work. Drawing on Bronfenbrenner's ecological systems model as an organizing scheme and emphasizing social justice issues, we describe how factors rooted in cultural contexts, families, and children themselves are likely to shape political development. In the second section of the monograph, we argue for the importance and utility of studying major political events, such as presidential elections, and introduce the major themes, rationales, and hypotheses for a study of U.S. children's views of the 2016 U.S. presidential election. In addition, we apply a social-justice lens to political thought and participation, addressing the role of gender/sex and race/ethnicity in children's political development broadly, and in their knowledge and views of the 2016 U.S. presidential election specifically. In interviews conducted within the month before and after the election, we examined two overarching categories of children's political attitudes: (a) knowledge, preferences, and expectations about the 2016 election, and (b) knowledge and attitudes concerning gender/sex and politics, particularly relevant for the 2016 election given Hillary Clinton's role as the first female major-party candidate for the presidency. Participants were 187 children (101 girls) between 5 and 11 years of age (M = 8.42 years, SD = 1.45 years). They were recruited from schools and youth organizations in five counties in four U.S. states (Kansas, Kentucky, Texas, and Washington) with varying voting patterns (e.g., Trump voters ranged from 27% to 71% of county voters). The sample was not a nationally representative one, but was racially diverse (35 African American, 50 Latinx, 81 White, and 21 multiracial, Asian American, Middle Eastern, or Native American children). In addition to several child characteristics (e.g., age, social dominance orientation [SDO]), we assessed several family and community characteristics (e.g., child-reported parental interest in the election and government-reported county-level voting patterns, respectively) hypothesized to predict outcome variables. Although our findings are shaped by the nature of our sample (e.g., our participants were less likely to support Trump than children in larger, nationwide samples were), they offer preliminary insights into children's political development. Overall, children in our sample were interested in and knowledgeable about the presidential election (e.g., a large majority identified the candidates correctly and reported some knowledge about their personal qualities or policy positions). They reported more information about Donald Trump's than Hillary Clinton's policies, largely accounted for by the substantial percentage of children (41%) who referred to Trump's immigration policies (e.g., building a wall between the United States and Mexico). Overall, children reported as many negative as positive personal qualities of the candidates, with negative qualities being reported more often for Trump than for Clinton (56% and 18% of children, respectively). Most children (88%) supported Clinton over Trump, a preference that did not vary by participants' gender/sex or race/ethnicity. In their responses to an open-ended inquiry about their reactions to Trump's win, 63% of children reported negative and 18% reported positive emotions. Latinx children reacted more negatively to the election outcome than did White children. Girls' and boys' emotional responses to the election outcome did not differ. Children's personal interest in serving as U.S. president did not vary across gender/sex or racial/ethnic groups (overall, 42% were interested). Clinton's loss of the election did not appear to depress (or pique) girls' interest in becoming U.S. president. With respect to the role of gender/sex in politics, many children (35%) were ignorant about women's absence from the U.S. presidency. Only a single child was able to name a historical individual who worked for women's civil rights or suffrage. Child characteristics predicted some outcome variables. For example, as expected, older children showed greater knowledge about the candidates than did younger children. Family and community characteristics also predicted some outcome variables. For example, as expected, participants were more likely to support Trump if they perceived that their parents supported him and if Trump received a greater percentage of votes in the children's county of residence. Our data suggest that civic education should be expanded and reformed. In addition to addressing societal problems requiring political solutions, civics lessons should include the histories of social groups' political participation, including information about gender discrimination and the women's suffrage movement in U.S. political history. Providing children with environments that are rich in information related to the purpose and value of politics, and with opportunities and encouragement for political thought and action, is potentially beneficial for youth and their nations.