This paper examines how housing market overvaluation—measured by the price-to-rent ratio and its deviations from long-term trends—affects the transmission of monetary policy. Using U.S. metropolitan-level data and three measures of monetary policy shocks, we find that house prices respond more strongly to policy rate changes in overvalued markets. Examining buyer heterogeneity, we show that investor demand, proxied by non-owner-occupied purchases, declines more sharply after monetary tightening in these markets. These results are consistent with models of extrapolative beliefs and suggest that monetary policy can serve a stabilizing role during housing booms.