This study aims to determine the causal relationship between the Rupiah Exchange Rate and the Indonesia Composite Index in Indonesia in 2007.1 – 2021.6. The method used in this research is descriptive and quantitative methods. In this research, the data used is secondary data. The analysis used in this research is using the Granger Causality Test method with the help of eviws 10.0. The results showed that the results of the data stationarity test showed that all research variables were statistically stationary at the first level of differentiation. This can be seen in the ADF value of the Indonesia Composite Index variable of -11.29, the exchange rate of -12.96 where the value is smaller than the critical value. The optimal lag test results show that the recommended optimal lag value is lag 1 with the consideration that changes in one variable in the model will affect other variables within a month. Granger causality test shows that there is a unidirectional causality relationship, there is a unidirectional causality between the exchange rate and Indonesia Composite Index variables and vice versa at the 5% significance level (value = 0.05).