This article investigates the relationship between foreign investors’ trading behaviour and political election events in South Korea and the effect of the relationship on the financial markets via a bivariate GARCH (1,1) model analysis. The empirical results show that the KOSPI 200 index return (total trading volumes of spot) and the derivatives volume have a negative (positive) relationship for foreign investors. South Korea shifted to a free floating exchange rate system, however, it did not have an effect on foreign investors’ trading behaviour. In particular, foreign investors showed significant decrease in trading options contracts during the parliamentary election periods and the parliamentary elections stabilized derivatives trading volatility. It is evident from the results that the presidential elections create far more financial uncertainty in comparison to parliamentary elections.