This paper aims to deepen our understanding of the relationship between firms’ internationalization and their sustainability development. We expected firms with a higher level of internationalization to exhibit better environmental management and performance. A sample of 287 publicly traded firms in the energy and energy‐related utilities sector was used to test these relationships. We focused on the energy sector, as energy production and supply have historically accounted for the lion’s share of global greenhouse gas emissions. We found that firms’ level of internationalization had a positive effect on their environmental management, whereas its effect on environmental performance was not found to be significant. We also tested whether these relationships change when firms’ internationalization is oriented towards developing countries. Upon a closer look, the relationship was found to be significant between internationalization towards developing countries and better environmental management, thus contributing to the line of literature that does not support the pollution haven hypothesis.