This paper analyses the factors influencing the level and volatility of real house prices in a panel of OECD countries over the period 1980-2005. Results suggest that real house prices tend to rise proportionally with real household incomes, while declines in structural unemployment and real interest rates are associated with higher real house prices. The process of mortgage market deregulation has coincided with a noticeable increase in real house prices in OECD countries, while high rates of leverage are found to amplify house price volatility. Estimates suggest that tax reliefs on mortgage debt financing costs tend to be capitalised into real house prices and may also amplify price volatility, reflecting the tendency for such policies to encourage leverage. While higher transaction costs are associated with lower house price volatility, this effect is modest compared to the impact of banking supervision. Indeed, prudential banking supervision and policies designed to contain the excessive build-up of leverage are shown to significantly reduce the extent of house price volatility, underscoring the importance of ongoing efforts to reform prudential frameworks in OECD countries.