The National Building Code (NBC) was developed to standardize construction practices and reduce the incidence of building collapse in Nigeria. Despite its strategic importance, implementation has remained weak, with many states yet to domesticate the Code, resulting in fragmented compliance and inconsistent enforcement nationwide. This study examines the legal,institutional, and professional challenges affecting effective NBC implementation, with emphasis on compliance gaps, enforcement mechanisms, and legal remedies. A qualitative documentary research design was adopted, drawing data from NBC documents, state building laws, Nigerian Building and Road Research Institute (NBRRI) building collapse reports (2000–2024), professional regulatory guidelines, and peerreviewed literature. Thematic content analysis, trend analysis, and international benchmarking were employed. Findings reveal that nondomestication of the NBC at the state level constitutes the most significant legal barrier, as the Code lacks automatic enforceability within Nigeria’s federal structure. Institutional challenges include inadequate staffing of building control agencies, obsolete material testing infrastructure, weak inter-agency coordination, and corruption. Professional conflicts among builders, architects, engineers, planners, and contractors further undermine accountability, while the informal construction sector—responsible for over 70% of building activities—operates largely outside regulatory oversight. Building collapse incidents peaked between 2016 and 2020, correlating with rapid urbanization and weak enforcement. Comparative analysis with Singapore, Ghana, South Africa, and the United States reveals major regulatory gaps in Nigeria, particularly in digital permitting, independent inspections, and deterrent sanctions. The study recommends mandatory nationwide domestication of the NBC, establishment of a National Building Regulation Commission, adoption of digital approval systems, compulsory builder-led supervision, and strengthened legal accountability