Eco–labeling is one way to assure consumers of the environmental suitability of products they purchase. However, several arguments have evolved to show that the use of eco–labels poses barriers to international trade. This exploratory study seeks to determine whether or not the use of eco–labels is a barrier to international trade in reference to the World Trade Organization (WTO) and International Standards Organization (ISO) principles. Product related production processes and methods (PPMs) and non–product related production processes and methods (npr–PPMs) have been a major source of disagreement among researchers. Our study examined the ISO criteria for eco–labeling that demand that life–cycle assessment (LCA) including both PPMs and npr–PPMs be satisfied. One of the major problems uncovered is the difficulty in identifying corresponding environmental variables for LCA requirements since environmental conditions vary among countries. We provide some recommendations and conclude that eco–labeling is not intended to be a barrier to international trade provided that it is not advocated under the pretext of protectionism.