Abstract: This study aims to determine whether there are differences in trading-volume activity and abnormal return before and after stock split event. The population in this study is 40 companies with a sample consisting of 23 companies listed on the Indonesia Stock Exchange period 2010-2014. The data used in this study include the date of stock split announcement that is used as event date, daily closing stock price of the company that performs stock split in observation period, Daily Joint Stock Price Index (IHSG) daily, number of stocks traded daily and number of stocks outstanding or listed. The results showed that there was no significant difference in trading activity volume and abnormal return before and after the event. This indicates that investors in Indonesia have not anticipated rapidly the information it receives in the capital market and may even be an investor assumes that stock split events are not good news. In addition, investors and issuers need to pay attention to external factors such as economic factors, political instability, and market conditions because it will indirectly affect the activities of the capital market.