Environmental degradation is a general problem but it is often more serious in developing nations where levels of awareness are lower than in industrialized countries. There is, therefore, a need particularly in developing countries to increase pro-environmental attitudes and behaviors. In this paper, we report the results of a quasi-experimental study designed to change environmental attitudes and environmental behaviors among 263 science pre-service teachers. The treatment consisted in the form of a green chemistry curriculum. We found statistically reliable changes in environmental attitudes, as measured by the New Ecological Paradigm, and in eight self-reported environmental behaviors. The Bayesian t-test suggests that the evidence for the changes to have been the result of the green chemistry curriculum is decisive. We conclude that the green chemistry curriculum constitutes a suitable context: (a) for supporting pre-service teachers in their development of pro-environmental attitudes and (b) for changing the levels of self-reported pro-environmental actions.