This study investigates the behavior of foreign investors’ investment decisions in Vietnam stock market, an emerging stock market. The study employs time series quarterly data over the period from quarter 1, 2005 to quarter 4, 2018 which extended before and after the global financial crisis in 2008. The results indicate that foreign investors were positive feedback traders in Vietnam stock market. Concurrently, the findings of GARCH model also reveal that foreign investors’ investment decisions in Vietnam stock market were influ-enced by unusual past shocks. However, these decisions lack the stability and periodicity. These are some empirical evidence on foreign investors’ behavior of investment decisions in Vietnam stock market. These results also provide the authorities in Vietnam a basis to develop suitable policies in order to comprehensively restructure the stock market to aim the international integration and increasing the capacity of capital attraction for foreign investors.