Equity duration plays a central role in the transmission of monetary policy to equity markets. Using dividend futures and empirical estimates of aggregate equity duration, I show that stock market reactions to monetary policy are stronger when equity duration is high. In the cross-section, variation in equity duration explains the heterogeneous sensitivity of U.S. stock returns to monetary policy across a broad set of firm characteristics, including dividend yield, market-to-book ratio, cash flow-to-price ratio, profitability, investment growth, and payout ratio. In contrast, differences in be- tas, size, or financial constraints do not account for this heterogeneity. An asset-pricing model in which heterogeneity stems solely from differences in cash flow maturity can reproduce these new empirical findings and clarifies the underlying duration channel.