Massive expansion of urban areas leads to land use/land cover (LULC) changes which significantly alter the hydrology of river basins. Yet, systematic and logical information on the spatio-temporal dynamics of urban LULC changes of African river basins, Kenya inclusive is scanty. This study established the spatio-temporal dynamics in urban LULC change in Nanyuki and Likii sub-catchments in the Upper Ewaso Ng’iro North River Basin from 1985-2018. This was achieved mainly using Landsat satellite images for 1985, 1995, 2008 and 2018, topographic, Open Street and urban plan maps. A pixel based supervised classification using Maximum Likelihood Algorithm and post-classification comparisons were used in the analysis. The study established eleven LULC types, seven of which were urban and four non-urban. In 1985, urban LULC types occupied a relatively small portion of 869Ha (3.4%) but continuously expanded in all directions. Residential LULC registered the highest overall change of 2176.2Ha (8.5%). Overall annual rate of urban LULC change was established at 0.42% with period 1995-2008 having the highest annual rate of 0.98%. These findings can be incorporated in urban spatial planning and in the assessment of the effect of the continuous urban land expansion on the river basin hydrology.