Given the increasing convergence and globalization of economies and markets, the expansion of international communications, the growing volume of global trade, and changes in the monetary policies of major economies such as the United States and the Eurozone, the impact of these changes on the macroeconomic variables of other countries has become particularly significant. Iran's economy, which is considered a small open economy in terms of concepts and performance, is connected to the global economy through financial and trade channels. The present study examines the spillover effects of U.S. Federal Reserve monetary policies on Iran’s banking credit during the years 2009–2023 (1388–1402 in the Iranian calendar), using the System Generalized Method of Moments (System GMM) econometric technique. The results indicate that the U.S. interest rate, bank capital, profitability, bank size, banking risk, ownership, liquidity, and macroeconomic variables all have a positive impact on the volume of credit provided by Iran’s private and state-owned banks. Accordingly, in order to shield Iran's economy from external shocks and disturbances, economic policymakers must consider the economic policies of other countries and develop optimal strategies. These should mitigate the negative effects of external shocks and, during periods of economic boom, amplify the positive spillover effects to foster the growth and prosperity of Iran’s economy.