In Ireland’s housing crisis, a growing population of renters, known as licensees—, ive under residential licence arrangements, including Rent-a-Room schemes, head-tenant sublets, and other unregulated lets. Unlike tenants protected by the Residential Tenancies Act (RTA), licensees have no formal recognition, limited legal safeguards, and no access to dispute-resolution mechanisms, leaving them uniquely vulnerable to eviction, poor standards, and arbitrary rules. Using a informal housing lens, this study employs a mixed-methods approach, combining focus groups with licensees and housing advisors, interviews with legal and policy experts, analysis of RTB tribunal decisions, and review of government data. Findings reveal systemic inequities, including deliberate mislabelling of contracts to evade tenant protections, tax incentives favouring landlords without safeguarding licensees, judicial reliance on substance-over-form interpretations, and fragmented guidance and support. The research highlights the structural precarity of licensees, particularly students, low-income workers, and migrants, and underscores the urgent need for policy interventions to provide rights, protections, and clearer information for this under-regulated sector.