Academics and policymakers have argued that the ability of low- and moderate-income families to move into desirable suburban areas is constrained by the high cost of housing. Local zoning and other forms of land use regulation are believed to contribute to increased housing prices by reducing supply and increasing the size of new housing. Suburban restrictions on rental housing are particularly likely to reduce mobility for low-income families. In this paper, I employ an instrumental variables approach to examine the effects of zoning on the quantity and price of rental housing in Massachusetts, using historical municipal characteristics to instrument for current regulations. Results suggest that communities with more restrictive zoning issue significantly fewer building permits for multifamily housing but provide only weak evidence of the effects of regulations on rents. The lack of effects on rents may reflect the low level of multifamily development, while analysis is complicated by development of subsidized housing under the state's affordable housing law. (Contains 4 figures, 9 tables and 25 footnotes.)