Landlords are essential actors within the rental housing market, and there is much to be learned about their willingness to participate in rental assistance programs that improve access to stable housing. Because the success of these programs, such as the Mobility (Location-Based) Voucher program in Pittsburgh, Pennsylvania, can be derailed by landlord opposition, it is important to test strategies that increase landlords' participation. Using data from a unique survey of Pittsburgh landlords, we found that exposing landlords to an asset-framing narrative that highlighted the social, economic, and health benefits of receiving a mobility voucher increased landlords' reported willingness to rent to a mobility voucher recipient by 21 percentage points. Reported willingness was also higher among landlords who believed that housing affordability was connected to health. Our findings offer insight into how to increase landlords' participation in affordable housing programs that require their engagement to succeed.