Urban Heat Island (UHI) occurs when cities record higher temperatures than surrounding rural areas due to Land Use/Land Cover (LULC) modification and anthropogenic heat. In Lagos metropolis, rapid urbanization has altered LULC, but spatiotemporal UHI dynamics over three decades remain poorly quantified. This study analyzed UHI dynamics in Lagos metropolis from 1984 to 2013 using remote sensing data from Landsat Thematic Mapper (TM) 5, Enhanced Thematic Mapper Plus (ETM+) 7, and Operational Land Imager (OLI) 8 imagery. Land Surface Temperature (LST) was retrieved from thermal bands, and urban–rural extents were delineated through supervised classification from multispectral bands in GIS. UHI zones were identified using mean LST thresholds for each time period. Urban built-up area expanded while rural open land declined, intensifying UHI. Urban LST increased from 24.76°C in 1984 to 28.59°C in 2013, and UHI extent grew from 125.01 km² to 319.38 km², a 155.4% increase. Findings confirm that LULC change driven by urbanization is the primary driver of UHI intensification in Lagos. Mitigation should prioritize increasing urban vegetation and high-albedo roofing. Street canyon design to enhance wind circulation is critical along the Ifako/Ijaye, Oshodi/Isolo, and Lagos Island corridor.