In November 2022, the German government decided to withdraw from the Energy Charter Treaty (ECT). After a long campaign to modernise the ECT, the EU now also prepares for an exit. In the political and legal discourse, the decision to withdraw is partly welcomed and partly criticised, interestingly in both cases with reference to a successful energy transition. This article takes up this seemingly contradictory reasoning and examines various aspects of the withdrawal decision regarding the energy transition. In particular, it examines the objectives and core provisions of the ECT, investment disputes decided on the basis of the ECT that are relevant to the energy transition, ECJ case law on the applicability of the ECT in intra-EU cases, the content of the Agreement in Principle on a modernised Energy Charter Treaty, as well as the consequences of the withdrawal decision and options for mitigating its harmful effects. The study shows that the assessment of the withdrawal decision is multifaceted and complex. Overall, we conclude that withdrawal at this point in time serves the interests of energy transition and climate protection better than a switch to a modernised ECT with subsequent continuation or withdrawal.