Thesis advisor: Andrew Prevot / Fr. Sergii Bulgakov (1871-1944) produced an extensive theological corpus exploring the concept of “Sophia” in Eastern Orthodox thought, practice, and spirituality. Writing from within the school of modern Russian religious thought, his “sophiology” has been the subject of controversy and misconception since his exile from the Soviet Union in 1922. Although there has been a renaissance of sorts in the 2020s of Bulgakov’s thought in Orthodox and ecumenical spaces, there has been little explicit treatment of his sophiology or its significance in shaping his dogmatic theology. The primary goal of this dissertation is to elucidate the concrete role of Sophia specifically within Bulgakov’s doctrines of the Trinity and creation. Tracking how Sophia operates in both her divine and creaturely roles within Bulgakov’s conception of the God-world relationship, the project demonstrates the essential role she plays not only in understanding Bulgakov’s dogmatic theology on its own terms but also in how one might consider retrieving Bulgakov for more constructive theological ends. To this end, the final chapters of the dissertation explore how Bulgakov’s theology creation is fundamentally shaped by his understanding of a sophianic Trinity while placing such sophiological conclusions into conversation with a constructive theology of the icon, French psychoanalytic philosophers Julia Kristeva and Luce Irigaray, and ecofeminism. In this way, the dissertation looks to Bulgakov’s use of Sophia as a potential source for the development of an Orthodox ecofeminist theology, critically and charitably exploring the feminine character of Sophia in Bulgakov, her relationship to the earth, “feminine” subjectivity, and the Eastern Christian iconographic tradition. Within his doctrines of Trinity and creation, Bulgakov discusses (1) the divine Sophia as the divine world, ousia of God, and her hypostatic relationship to the Father, (2) the hypostatsization of divine Sophia as the Son and the Holy Spirit, as well as her kenotic participation in both divine and creaturely worlds through the second and third divine persons, (3) how Sophia operates in the doctrine of creatio ex nihilo and how her presence shapes different definitions of divine and creaturely “nothing,” (4) Sophia, divine “femininity,” and her significance for theological anthropology, and (5) the connection between Sophia and “mother Earth” and humanity’s relationship to the organic world. Each of these points are treated in depth as the argument of the dissertation develops in the order of chapters. / Thesis (PhD) — Boston College, 2024. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Theology.