Most IIAs do not exclude taxation from their scope of application and are silent on their relationship with DTCs. This means that investors can be protected against tax-related measures adopted by host states that violate the IIA’s substantive protections, including measures that may simultaneously fall within the scope a DTC signed by the host state. This paper explores the extent to which ISDS claims involving domestic tax policies have the potential to overlap with the subject matter covered by DTCs and MAPs. In doing so, it will examine recent cases that illustrate such potential for interaction. It will then make suggestions in the form of treaty drafting approaches that states can adopt in their IIAs to regulate possible conflicts between the two regimes.