Housing is a critical component of people's lives. Unfortunately, finding affordable rental housing in the U.S. has become increasingly difficult. Additionally, there is an increasing need for solutions to this crisis that rely less on federal funding. One proposed market solution for affordable housing is missing-middle housing (MMH). This dissertation, structured in three chapters, poses several questions about MMH’s potential to provide affordable rental housing. Chapter I is a literature review examining MMH's potential to provide affordable housing. The review finds that many municipalities have used the MMH model to implement regulatory changes at the state and local levels to increase housing supply. The most prevalent literature addresses the zoning challenges to MMH. There are two types of literature on this topic: the earlier articles focus on case studies, while the second documents the effects of the zoning changes on the supply or price of housing, with very few documenting increases in the production of affordable MMH. There are a few articles that address other challenges of implementing MMH. Chapter II analyzes text from two sets of interviews with planners and developers to examine how MMH works in practice and how it is incentivized across the US. It highlights the challenges of implementing zoning reform and the lessons learned by planners. It finds that MMH's biggest challenge is community opposition. Developers shared that, in very limited instances, MMH can be used to provide affordable housing without public subsidies. Chapter III examined affordable MMH within the City of Atlanta through a review of zoning policy, a GIS analysis of potential locations for small missing middle housing (1-4 units and ADUs), and a pro forma analysis of project costs. The analysis identifies ways to improve Atlanta zoning to increase allowances for MMH, recommending that more residential zoning districts allow more units. The GIS analysis identifies 2,367 parcels as candidates for SMM and 291 parcels as candidates for ADUs. The final analysis finds that small missing-middle housing cannot be built in the City of Atlanta at affordable levels without subsidies.