In its infancy, corporate social responsibility (CSR) focused on environmental issues rather than the provision of a wider array of support to local communities. Today, CSR includes strong partnerships between multinational corporations and nongovernmental organizations (NGOs). Previous research has demonstrated that corporations that partner with NGOs are more visible to their key stakeholders. Through a longitudinal, in-depth study of Merck Thailand and the Raks Thai Foundation in Bangkok, Thailand, this case study identified best practices for a multinational company interested in partnering with a local NGO. From those practices, the research identified the key principles that sustain the partnership: leadership, communication, collaboration and innovation, competencies and culture, and sustainability. Leadership includes taking risks and being a visionary in order to build and sustain CSR partnerships. Communication includes external communication that occurs between the CSR partners and internal communications within each organization involved in the partnership. Competencies and culture involve identifying the skill levels necessary to sustain a successful CSR partnership and to identify cultural barriers between the partner organizations. Sustainability includes developing a long-term CSR partnership built on trust and mutual respect. These principles are useful to corporate and NGO executives who are interested in building sustainable relationships that can help their organizations meet the needs of their stakeholders.