This chapter analyses the FET standard included in the EVIPA. It begins with an overview of FET provisions within the context of IIL, followed by an examination of FET claims related to policy measures aimed at environmental protection, as seen in investment arbitration practice. Building on this foundation, the chapter then evaluates the FET provisions under EVIPA. The findings of this study highlight that the FET clause in EVIPA is more clearly defined compared to the language typically found in traditional FET clauses. This clarity offers greater assurance to the state in pursuing its policy objectives, as long as the measures undertaken do not fall within the outlined scenarios. Additionally, the chapter emphasises that the restriction on assessing legitimate expectations at the inception of the FET standard limits the potential for this factor to be interpreted beyond the original intentions of the parties. Importantly, the circumstances leading to a breach of the fundamental FET standard have already been codified in Vietnam’s national legislation, indicating a transparent legal framework.