The problem and the solution. A focus on collective, as opposed to individual learning, points to the social network component of learning. Collective learning is fundamentally concerned with social interaction and the development of relational synergies.A key challenge to understanding social interaction is the influence of trust. Trust is important for social capital development and thus for collective learning.This article addresses a significant gap in the literature by reviewing the literature on collective learning, trust, and social capital theory and proposing a set of propositions for further research.The article also identifies a number of implications for HRD in tandem with each proposition.