In this paper we investigate correlation dynamics and diversification properties of US dollar-denominated debt issued by governments of frontier markets. Our analysis is on the aggregate, regional, and country level, with a sample covering 29 countries over the period 2001-2013. We show that the correlation between the returns of frontier government bond markets and US government bonds is time-varying, but on average close to zero. Correlations with US investment grade corporate bonds, US corporate high yield bonds, and US dollar-denominated debt issued by governments of emerging markets are substantially higher, which limits diversification benefits for investors who already own these asset classes.