Purpose: The purpose of this paper is to shed new light on the way the cross-sector collaboration (CSC) process can foster gender-focused sustainability initiatives to improve female workers’ conditions in developing countries. The study does so by introducing and examining the influence of nonprofit boundary work during the CSC process. Design/methodology/approach: The paper is based on thirty-four interviews and qualitative fieldwork. It draws on a case analysis of a regional CSC between multiple organizations operating locally in the apparel industry of Bangladesh, a developing country. Findings: Scaffolding work in the CSC formation stage – performed by development agency implementers who construe boundaries – and sensitization work in the CSC implementation stage – performed by a non-governmental organization (NGO) implementers who blur and expand boundaries – emerge as two conceptual categories of nonprofit boundary work. This allows NGO implementers to identify and enable the agency of sustainability envoys or socially privileged individuals who capitalize on their social credentials to support female workers in the factory and in the community. Originality/value: The study offers novel insights into the CSC process. It contributes to the CSC literature and the literature on boundary work, with a focus on gender-focused sustainability initiatives for female workers in developing countries.