This conceptual paper addresses the nature of value creation in professional service firms (PSFs). An extensive number of scholars have been looking at PSFs within law, consulting and engineering to understand knowledge as sources of competitive advantage. A dominant part of this literature build on agency theory to suggest that information asymmetry is an important characteristic and precondition of value creation in professional services. This paper identifies a contradiction in the notion of information asymmetry in reference to professional services firms. The paper reviews theoretical contributions explaining the value creation processes in PSFs. While the context of professional services might be considered marginal in reference to agency theory, knowledge has been identified as one of the key sources of competitive advantage in the 21st century, and understanding how to develop and leverage such sources of advantage has gained extensive interest. In addition, the context of knowledge intensive and professional services has been referred to as extreme and strategically relevant to understand knowledge based value creation. We argue that it is necessary to revisit the assumption of information asymmetry for two main reasons, First, any asymmetry that is proposed to exist is that of knowledge rather than information. Secondly, value creation in the context of PSFs is characterized by mutuality rather than asymmetry as co-production with clients as a core component in PSFs value creation. While PSFs might have superior esoteric professional knowledge, buyers often have superior knowledge of their own context and problem. Both of these types of knowledge are relevant in the value creation in PSFs due to the contextual and customized nature of the services they provide. Two important contributions are suggested in the paper, First, the characteristics of value creation of PSFs should be revised and extended by the inclusion of knowledge asymmetry and mutuality. This is important for practitioners in that the co-operative and mutual nature of value creation needs to be recognized and nurtured, which has impact of the conduct of both suppliers and buyers of professional services. Secondly, this more complex nature of value creation needs to be recognized from an institutional perspective in that the certification of professionals should incorporate and promote the mutuality and the importance of client needs while at the same time emphasising esoteric professional knowledge and attitude and the desire to deliver what is objectively best for the client.