In this study, we developed and tested a theory of how human resource practices affect the organizational social climate conditions that facilitate knowledge exchange and combination and resultant firm performance. A field study of 136 technology companies showed that commitment-based human resource practices were positively related to the organizational social climates of trust, cooperation, and shared codes and language. In turn, these measures of a firm's social climate were related to the firm's capability to exchange and combine knowledge, a relationship that predicted firm revenue from new products and services and firm sales growth.