The energy taxation directive 2003/96/EC (ETD) is currently under discussion, twenty years after its adoption and after several failed reform attempts. This directive does not reflect the current European climate and energy policy framework and is not adequate to address the challenges of climate change and the green transition. Moreover, it not only fails to protect the environment but also endangers the proper functioning of the internal market. Through a legal analysis, this contribution aims to examine the origin and evolution of the ETD until the latest Commission proposal, which is currently under negotiation, in order to investigate the weaknesses of this directive, the novelties of the recent proposal, and what risks European environmental and fiscal objectives would run if the negotiations are not successful.