This article investigates the role of Catholic and non-Catholic local actors in shaping missionary activities in seventeenth-century Ottoman Europe. It examines jurisdictional conflicts and collaborations between Bosnian Franciscan friars, Ragusan merchants, Ottoman officials—particularly judges—and Serbian Orthodox clergy, whose interactions shaped the local landscape of Catholicism and defined the limits of Catholic engagement. Drawing primarily on Catholic missionary sources, the study argues that analysing missions through interconnected local, regional, and global lenses, while foregrounding the agency of local actors, provides a more nuanced understanding of early modern Catholicism. By expanding historiographical approaches that have primarily focused on Catholic missions outside Europe, the article advocates for the inclusion of Ottoman Europe as a significant yet understudied site of Catholic missionary activity. It further highlights the jurisdictional and institutional tensions within Catholic expansion and governance, revealing the complexities of missionary engagement in a politically fragmented and religiously plural environment.