A growing number of firms are considering the incorporation of environmental thinking into their business strategies, hoping to improve their competitiveness. In this paper, we analyze the effects of pollution prevention and service stewardship capabilities on firm differentiation advantage in the third‐party logistics industry. Since prior research claims that complementary assets play an important role in fully understanding the environmental‐management‐competitiveness link, we furthermore examine the moderating role of environmental communication on the pollution‐prevention‐differentiation and the service‐stewardship‐differentiation linkages. We theoretically base our research in natural‐resource‐based thinking. Drawing on survey data, we apply multivariate regression and moderation analysis. The results highlight that pollution prevention and service stewardship capabilities can help third‐party logistics providers to achieve a differentiation advantage. Also, the results show that environmental communication moderates the effect of pollution prevention on differentiation advantage and can hence be considered a valuable complementary asset.