Globalization creates an increased tension around the responsibility of a multinational firm for the labor practices of its external providers. As supply chain networks extend outside the boundary of the firm, multinational firms seek to manage reputational risk associated with potential health and safety violations attached to their products while not having full legal oversight of an external provider compared to an internal facility that is wholly owned or a subsidiary. In this study, I investigate how firms govern health and safety issues across the boundary of the firm and how the boundary of the firm shapes a firm’s use of formalization or collaboration for a supplier. Through personal interviews with corporate social responsibility (CSR) and environmental health and safety (EHS) professionals and thematic coding of interviews, I analyze how each interviewee differently conceptualizes the boundary of their firm and operationalizes governance practices around the boundary of the firm to meet strategic goals. I find that firms primarily focus on formalized governance with external providers and collaborative governance with internal providers, but there is a trend toward more collaborative governance practices across the boundary of the firm. This leads some firms to re-conceptualize the boundary of the firm to strategically select some external providers for collaboration. These findings have significant implications for the current theory of the firm, as they demonstrate the role of governance practices in shaping the boundary of the firm in CSR settings.