How does spatial scale affect support for public policy? Does supporting housing citywide but “Not In My Back Yard” (NIMBY) help explain why housing has become increasingly difficult to build in once-affordable cities? I use two original surveys to measure how support for new housing varies between the city scale and neighborhood scale. Together, an exit poll of 1,660 voters during the 2015 San Francisco election and a national survey of over 3,000 respondents provide the first experimental measurements of NIMBYism. While homeowners are sensitive to housing’s proximity, renters typically do not express NIMBYism. However, in high-rent cities, renters demonstrate NIMBYism on par with homeowners, despite continuing to support large increases in the housing supply citywide. These scale-dependent preferences not only help explain the deepening affordability crisis, but show how institutions can undersupply even widely supported public goods. When preferences are scale dependent, the scale of decision-making matters.