This study examines whether there is a causal relationship between selected stock markets in Asia and the US. Based on stock values from a sample of nine Asian stock markets, we find a positive correlation with US stock market prices in most cases, the exception being Vietnam. Our results indicate significant long-run and short-run causality in both directions between the Asian and US stock markets. These findings show that, while both sets of markets are integrated, there are still valuable opportunities for international investors to diversify their portfolios in the US and Asia.