<p>Unregistered private facilities make up the majority of healthcare establishments in Nairobi Kenya’s informal settlements or ‘slums. Facility registration ensures the minimum standard of quality of maternal, newborn, and child health (MNCH) care that is provided and allows for facilities to access government resources. However, the process of registering facilities is a challenge for many private providers and poses significant barriers to the visibility and regulation of MNCH care in these catchment areas. To improve the quality of care in these areas, unregistered facilities need to be actively engaged in the process of regulation and incentivized to register as formal entities. This qualitative study, conducted by Jacaranda Health, a non-profit organization, forms part of a USAID-funded implementation research project—<i>Kuboresha Afya Mitaani—</i>taking place in two informal settlements in Nairobi, Kawangware and Mathare. The aim was to understand the financial, organizational, and social barriers that unregistered private facilities in Dagoretti and Starehe sub-counties have faced when considering or attempting to register and what changes could be made to promote registration. Findings identified that unregistered facility owners are willing to engage in conversations around registration, yet face significant financial, operational, and professional challenges—such as the need for infrastructure upgrades, irregular patient payment schemes, and corruption—that hindered their path to registration. These insights lead to a series of evidence-based recommendations, including a reduction in or financing for facility registration fees, expanding the formal healthcare workforce, and clearer directions on how to complete the registration process (including provision of accessible, stepwise information about regulatory bodies and financing options).</p>