For the stability of a country's economy, macroeconomic variables must be in a balanced structure with each other for economic stability. Changes in macroeconomic variables can affect each other as well as financial markets. On the other hand, monetary policy tools implemented by central banks appear as elements aimed at establishing or maintaining this balance. In this study, the relationships between selected macroeconomic variables such as inflation, interest rates, exchange rates and Borsa Istanbul 100 (BIST 100) index returns were examined. In this context, analyses were conducted using monthly data obtained from the electronic data distribution center system of the Central Bank of the Republic of Türkiye and Borsa Istanbul Historic Data Platform for the period January 2014 - June 2024. In the study, while examining the relationship between BIST 100 index returns and macroeconomic variables, firstly the stationarity of the series was examined and then cointegration test was applied to determine the existence of the relationship between the variables. Causality test was also applied to determine the direction of the detected relationship. In addition, variance decomposition tests were used to determine where the shocks in the variables originated from. It is thought that the findings may benefit for both investors and policy makers in decision-making processes.