Tax revenue plays a vital role in financing public services in Nigeria. However, its performance has shown significant fluctuations in recent years. This study investigates the influence of macroeconomic variables on tax revenue performance in South Africa over the period from the first quarter of 2000 to the third quarter of 2024, employing the Markov Switching Model (MSM). The analysis reveals that the effects of macroeconomic factors vary across different economic regimes. Specifically, inflation and interest rates are found to reduce tax revenue in the first regime but contribute positively in the second. Conversely, the exchange rate and current account balance enhance revenue in regime one, while exerting a negative influence in regime two. Notably, economic growth consistently promotes tax revenue across both regimes. These findings underscore the importance of accounting for prevailing economic conditions when assessing tax revenue dynamics. Policymakers should tailor fiscal strategies to these varying impacts in order to strengthen and stabilize tax collection. A clear understanding of the relationship between economic conditions and revenue performance is crucial for designing policies that support long-term fiscal sustainability.