One reason teams are seen to be a high-performance work practice (HPWP) is that the diversity of team member knowledge, skills and abilities, known as cognitive resource diversity supposedly brings new perspectives, information, ideas and resources to the solution of problems and the exploration and exploitation of opportunities. However, to date the performance of heterogeneous teams has been disappointing with the most common finding being increased conflict. Based on social identity and social exchange theories and building onto Mayer, Davis & Schoorman's (1995) classic integrative model of trust, this paper proposes that trust is a critical mediator in the relationship between cognitive resource diversity and within-team knowledge sharing.