Enforcing intellectual property (IP) rights abroad is not easy – not least because international IP treaties do not create global rights that can invoked in national courts. International investment law offers potential routes for overcoming these hurdles. Whenever investment treaties include IP rights as an investment and allow for investor-state dispute settlement (ISDS), investors can challenge host state measures affecting their IP rights in ISDS proceedings. As this article will show, this in turn offers a unique opportunity for invoking the standards of protection under international investment agreements (IIAs) to challenge host state compliance with international IP treaties. While challenging national IP regimes is an attractive option for right holders, these challenges potentially amount to a sea-change for the international IP regime and cause serious concern for host states. I however argue that most of the routes pursued by right holders under IIAs are unlikely to be successful. Investment protection standards such as fair and equitable treatment, umbrella clauses and most-favored nation treatment should not be construed to allow invoking alleged breaches of international IP norms in ISDS. Some IIAs however contain clauses that subject expropriation claims against compulsory licenses and other IP limitations to a test of consistency with the international IP rules governing these limitations. As they offer the only feasible route for investors to challenge host state compliance with international IP treaties, I review the implications of these clauses, recent reform proposals and suggest alternative mechanisms for aligning international IP and investment protection based on general international law.