The U.S. has a chronic shortage of reasonably-priced housing. Decades of policy and program intervention at federal, state, and local levels has not substantively alleviated this problem. Consequently, alarmingly high proportions of the population spend over 30% of their income on housing costs and are deemed housing cost-burdened. Housing cost-burdened households have a much lower quality of life than those that are not. Thus, the housing affordability problem is a serious social concern. Is this problem also holding back the U.S. economy? I explore whether the lack of reasonably-priced housing adversely impacted per capita gross domestic product (GDP) growth in the 100 most populous metro areas of the country. I use publicly available data for three time points (2000, 2010, and 2015) and changes in the proportion of cost-burdened households in metros as the experimental variable. I find that decreases in housing affordability had a statistically significant negative effect on economic growth in these metros. Over 80% of the national GDP is generated in U.S. metros, and increasing housing affordability there may help grow the U.S. economy. Therefore, policies to increase housing affordability, long seen as a social imperative, may well be an economic imperative also.