In this research, we estimate the association of firearm restrictions for domestic violence offenders with intimate partner homicides (IPHs), based on the strength of the policies. We posit that the association of firearm laws with IPHs depends on the laws': 1) breadth of coverage of high-risk individuals and situations restricted; 2) power to compel firearm surrender or removal from prohibited persons; and 3) systems of accountability that prevent prohibited persons from obtaining guns. We conducted a quantitative policy evaluation using annual state-level data from 1980 through 2013 for 45 US states. Based on the results of a series of robust negative binomial regression models with state fixed effects, domestic violence restraining order firearm prohibition laws are associated with 9% reductions in IPH. Statistically significant protective associations were evident only when restraining order prohibitions covered dating partners (-10%) and ex parte orders (-12%). Laws prohibiting access to those convicted of non-specific violent misdemeanors were associated with a 23% reduction in IPH rates; there was no association when prohibitions were limited to domestic violence. Permit-to-purchase laws were associated with 10% reductions in IPHs. These findings should inform policymakers considering laws to maximize protections against intimate partner homicide.