The WTO is often criticised for consistently refusing to accept the environmental measures of its Members due to their adverse impacts on international trade. The aim of this paper is to examine the recent developments in WTO law considering this clash between liberal trade and environmental protection. The analysis is based on the most recent US – Tuna II (Mexico)1 case, the third in the Tuna Dolphin line of case law. The paper shows that the Appellate Body still greatly favours free trade over the environment, but that some progress can still be found in the latest Tuna ruling. Notions of technical regulation, likeness, less favourable treatment, extraterritoriality and necessity are examined in light of this dispute. The paper also gives a broader perspective on the suitability of the Technical Barriers to Trade Agreement to endorse environmental protection in the form of ‘green trade barriers’, as well as suggestions for a new approach that the WTO Dispute Settlement Body should take in an effort to strike a balance between protecting the environment and facilitating economic prosperity through liberal trade.