Project execution in the construction industry faces major challenges, e.g. difficulty in coordination and cooperation. Operational procurement during project execution is no exception. In this paper we construct a maturity model, based on earlier work, consisting of six dimensions (goal, control, process, organization, information, technology) and five maturity stages (transactional-oriented, commercial-oriented, coordination, internal-optimized, external-optimized). The model can be used to determine the level of procurement maturity for each of the dimensions, and for the determination of a strategy for growth in the construction industry. With input from a major construction firm in the Netherlands, through simulating tooling, the model is evaluated for its contribution to growth in operational excellence. Results of the simulation show support for a relation between maturity growth and increased operational excellence.