The article investigates the impact of after-hours trading on Taiwan index futures, including Taiwan stock index (TAIEX) futures and Taiwan electronics sector index futures. Taiwan Futures Exchange launches afterhours trading session starting from May 15, 2017. The empirical results show that trading volume is positively correlated with price volatility, and open interest is either negatively correlated or insignificantly correlated with price volatility. In addition, there is some evidence which indicates that after-hours trading improves the price efficiency of Taiwan index futures.