In this paper, we seek to determine what factors drive the adoption of green purchasing among municipalities in Mexico and the success of their implementation. Given the lack of research and theory in the area, this study is exploratory in nature. We applied the green purchasing survey developed by Arizona State University to all municipalities in Mexico with a population of 25,000 or more inhabitants. Using the least absolute shrinkage and selector operator method (LASSO), we reduced the set of measures, which we then employed in a logistic regression to predict whether the municipality would adopt a green purchasing policy. We found that complementary environmental practices, department rules, and city-wide contracts to reduce purchasing costs have a positive and significant effect on the propensity to adopt green purchasing policies, but the time for routine low-cost purchases has a negative effect on green purchasing policy adoption. Then, using two-stage least squares, we developed a model of the factors leading to successful implementation of green purchasing. We found that complementary environmental policies, environmental practices, environmental program knowledge, and city-wide contracts to reduce purchasing costs are positively and significantly related to successful implementation. However, department resources and the time for routine low-cost purchase are significant, but negatively related.