Over the past three decades, local barriers to housing development have intensified, particularly in the high-growth metropolitan areas increasingly fueling the national economy. The accumulation of such barriers – including zoning, other land use regulations, and lengthy development approval processes – has reduced the ability of many housing markets to respond to growing demand. The growing severity of undersupplied housing markets is jeopardizing housing affordability for working families, increasing income inequality by reducing less-skilled workers’ access to high-wage labor markets, and stifling GDP growth by driving labor migration away from the most productive regions. By modernizing their approaches to housing development regulation, states and localities can restrain unchecked housing cost growth, protect homeowners, and strengthen their economies. Locally-constructed barriers to new housing development include beneficial environmental protections, but also laws plainly designed to exclude multifamily or affordable housing. Local policies acting as barriers to housing supply include land use restrictions that make developable land much more costly than it is inherently, zoning restrictions, off-street parking requirements, arbitrary or antiquated preservation regulations, residential conversion restrictions, and unnecessarily slow permitting processes. The accumulation of these barriers has reduced the ability of many housing markets to respond to growing demand.