This study investigates the asymmetric effects of exchange rate volatility on the trading value of the Tehran Stock Exchange using a Nonlinear Autoregressive Distributed Lag (NARDL) model. Quarterly data from 2002 to 2024 were collected from the Tehran Stock Exchange and the World Bank. Exchange rate volatility is decomposed into positive and negative shocks, while the price-to-dividend ratio (P/D) and per capita nominal GDP are included as control variables. The empirical results indicate the existence of a long-run equilibrium relationship. Positive shocks in exchange rate volatility significantly increase trading value, whereas negative shocks have no significant effect. The Wald test confirms the presence of long-run asymmetry. These findings highlight the asymmetric behavior of the stock market in response to exchange rate fluctuations and underscore the importance of implementing targeted policies to better manage the capital market during periods of heightened volatility and uncertainty. Moreover, the results suggest the need for stability-oriented policies to mitigate the adverse effects of exchange rate shocks. Overall, the study provides valuable insights for policymakers and investors, emphasizing that exchange rate dynamics play a critical role in shaping market activity, and that asymmetric responses should be carefully considered in market regulation and strategic decision-making.