This dissertation investigated predictors of scientific civic engagement among undergraduate students through a multimethod approach, focusing on how educational experiences shaped students' engagement with their communities using scientific skills. This multipart study addressed gaps in understanding how educational practices, identity, and sense of belonging can foster scientific civic engagement, with each of the three interconnected chapters employing distinct methods to explore this phenomenon. Chapter 1 introduces the Predictors of Scientific Civic Engagement (PSCE) survey, developed to assess undergraduates' attitudes, self-efficacy, knowledge, and intentions to engage civically using their science skills. Using cognitive interviews combined with psychometric statistical analyses, the validity of the PSCE survey was investigated to assess whether it was an accurate and reliable tool for measuring predictors of future civic engagement in populations of undergraduate students enrolled within STEM courses. This work contributed a novel instrument that educators and researchers can use to assess and help them to enhance civic engagement in undergraduate STEM educational contexts. Chapter 2 utilizes the PSCE survey to explore the influence of students' sense of belonging to the communities with which they engage with in civically-engaged courses on the predictors of scientific civic engagement and science identity. Through linear mixed model analyses of pre- and post-course survey data, the study revealed that students' pre-course sense of belonging to the communities with which they engaged during civically-engaged courses significantly impacted their engagement outcomes, highlighting the importance of inclusive and supportive learning environments in promoting scientific civic engagement. This chapter emphasized students' belongingness, specifically belongingness to the communities that they engage with during civic-science education, as a critical factor that should be considered in civically-engaged STEM curriculum design. Chapter 3 presents a qualitative case study investigating the sense of belonging mechanisms behind the findings of Chapter 2, with a particular focus on how Latine STEM students' identities shaped their community engagement within the El Paso community, a unique Latine community housing University of Texas El Paso and bordering Ciudad Juarez, Mexico. Through thematic analysis of interviews and other qualitative data, this chapter explored how personal, place, and scientific identities influenced motivations and strategies for civic engagement within El Paso. The findings highlighted the complex interplay between identity and engagement, providing valuable insights into how Latine STEM students navigate their roles as community-engaged scientists. Collectively, this dissertation underscores the need for integrating civic-oriented pedagogy into STEM education in culturally sensitive ways that consider the unique identities of STEM students in order to cultivate scientifically informed and socially responsible citizens. It addressed critical gaps in understanding how sense of belonging and identity influence engagement, offering practical recommendations for educators and policymakers. By employing a combination of validated instruments and multimethod approaches, this work offered comprehensive insights into enhancing scientific civic engagement. Ultimately, the intent of this work is to promote positive social change through informing the pedagogy and practice of civic engagement in science education. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]