Pre-print, Working paper: There are close to 3,000 international investment agreements (IIAs) that aim to protect and promote cross-border investment. Do they achieve their main purpose? This paper provides novel firm-level evidence on the effects of IIAs on location decisions of multinational enterprises (MNEs) in a multi-country context. It uses unique micro-level data on the location of MNEs' affiliates globally and country-pair data on the coverage and content of treaties over a twenty-year period (1990-2010). It finds that IIAs, in particular those with the investor state dispute settlement (ISDS), increase the probability of MNEs' first foreign entry when they are accompanied by a double-taxation treaty. This interaction between investment and tax treaties can have important policy implications.