Accessory dwelling units (ADUs) are a strategy for providing affordable rental housing. We suggest a typology of regulatory approaches in Long Island, New York, differentiating between jurisdictions that allow nonfamily/nondomestic employee renters in ADUs (Type 1), allow only family members and domestic employees in ADUs (Type 2), and do not allow any ADUs (Type 3). Content analysis, descriptive statistics, and t tests reveal that there is variation among occupancy and design regulations, suggesting that jurisdictional fragmentation and exclusionary zoning present obstacles to using ADUs as an affordable housing strategy.