PurposeThe environmental management literature has focussed on the analysis of the variety of strategic options with regards to environment protection, without providing an interesting detail of the transformation and change process between the different alternatives. Therefore, the purpose of this paper is to study pro-environmental change processes in firms, focussing on the width and the intensity of environmental measures implemented in a three-year period in different areas (productive process, product, management and supply chains).Design/methodology/approachPerforming a cluster analysis based on a sample of 303 Spanish firms, the study finds four categories of pro-environmental change.FindingsThe comparative analysis of these categories leads the authors to describe the pro-environmental change process as one with four stages that firms can go through. The first pro-environmental stage focusses on process measures. The second stage focusses on the adoption of management measures together with process measures. In the third stage, the firm moves after including measures in the product and in the supply chains. Companies that wish to advance further in this process, reaching the fourth stage of pro-environmental change, do so by increasing the intensity of the different measures adopted in previous stages, and through eco-innovation.Research limitations/implicationsThe main contribution of this paper relative to the previous literature is a more detailed vision of the strategic possibilities in environmental protection, providing information about the process of change and about how firms evolve to more advanced environmental strategy stages. Knowledge of this evolution process, little studied in the previous literature, helps us to understand the complexity and strategic significance of adopting environmental protection measures. This knowledge is useful for academics and for public and private managers responsible for designing and developing environmental strategy.Originality/valueOne of the most original findings of this paper points out that it is possible to identify a pattern of environmental change through which firms can evolve. In this change process, firms start by adopting process measures, while they adopt eco-innovation behaviour only in the most advanced stage of environmental proactivity.