Using 1995 Landsat Thematic Mapper (TM) imagery, 2013 and 2020 Enhanced Thematic Mapper Plus (ETM +) imagery, this study analyses changes in land use and land cover (LULC) in Nairobi during the last three decades. A quantitative method was applied involving the use of Geographic Information System (GIS) data to produce maps that depict LULC changes. The findings show that built-up areas increased while grasslands decreased during the examined period. Grasslands in Nairobi National Park, Karura, and Ngong’ forests display a high level of naturalness. The increase in built-up land use improved economically the areas where it occurred but led to negative environmental impacts. The main policy recommendation of this study is to regulate the type of buildings and the rate of new construction to curb this phenomenon. Similarly, instead of single homes, attached buildings should be adapted to reduce the extent of built-up areas.