We uncover a novel channel by which monetary policy affects the economy’s supply side through affecting risk premia. In this channel, monetary policy affects the effective risk aversion, that is, the price of risk in the economy. This impacts equilibrium R&D investments and, eventually, TFP growth. Using an asset pricing model, we construct measures of the price of risk shocks and show that increases in the price of risk decrease aggregate R&D. We then quantify the contribution of our channel to the overall R&D and TFP growth response to monetary policy shocks by constructing an endogenous growth model with time-varying risk aversion. Using the model, we find that the price of risk channel accounts for 20% of reaction of R&D and 33% of the reaction of TFP growth to unanticipated monetary policy.