Recently, increasing attention has been paid to building successful partnerships in information systems (IS) outsourcing. This study establishes partnership quality as a key predictor of outsourcing success. We propose a theoretical framework for outsourcing partnership based on a social, rather than an economic, perspective. We identify the partnership-related variables from the relevant literature and clarify the concept of partnership quality by distinguishing between its components and its determinants. We then examine the impact of partnership quality on outsourcing success. Hypotheses on partnership quality were tested for 74 outsourcing relationships between 36 service receivers and 54 service providers. Results indicate that partnership quality may serve as a key predictor of outsourcing success. Partnership quality was found to be positively influenced by factors such as participation, communication, information sharing, and top management support, and negatively affected by age of relationship and mutual dependency.