Research Summary We examined Seattle, Washington's Neighborhood Matching Fund (NMF), a unique neighborhood improvement program that provides city funding for projects organized within neighborhoods. We found an inverse relationship between NMF funding and violent crime rates, a relationship that is stronger in poorer neighborhoods. The relationship also is stronger as funds accumulate within the neighborhoods over time. These findings suggest that investment and neighborhood participation can have both short‐term and long‐term crime reduction effects. Policy Implications The Neighborhood Matching Fund program is associated with significant reductions in crime, even though the program and its projects are not aimed specifically at crime reduction. This observation suggests that policies that encourage neighbors to interact with each other and that facilitate interactions and physical improvements can help reduce crime by improving neighborhood conditions and social relationships. Investments in neighborhoods by the city also can help counteract the negative effects of private disinvestment.