The objectives of this research were: (1) To examine the outcomes and key factors of success (KFS) related to ISO 14001 certification, (2) to compare and contrast these in private organizations (PRIVOs) and public organizations (PUBOs), and (3) in the under-explored context of an Arab Gulf country with an emerging economy: The United Arab Emirates. We used an exploratory, qualitative research approach, based on semi-structured interviews with the environmental managers of 14 UAE organizations from the private and public sector. The five major outcomes of ISO 14001 certification were improved: (1) Environmental performance, (2) organizational reputation and relationships with stakeholders, (3) organizational efficiency, (4) environmental management (EM) practices, and (5) environmental awareness. These outcomes were shared by PRIVOs and PUBOs, although improved resource management, improved relations with stakeholders, and improved EM practices were more common in PUBOs, and improved organizational efficiency was more common in PRIVOs. The six KFS for implementation were: (1) Senior management's support, (2) employees' awareness, involvement and competence, (3) government initiatives and commitment, (4) sufficient organizational resources, (5) adoption of a continuous, integrative, and collaborative approach, and (6) the use of external consultants. These KFS were shared by PRIVOs and PUBOs, although government initiatives and commitment were more common in PUBOs, and sufficient resources were more common in PRIVOs. Our study contributes to a better understanding of environmental management system implementation in emerging countries in general, and in Arab Gulf countries particularly. Our study has implications for business leaders, policy makers, EMS professionals, and educators in the UAE and other emerging countries.