An urban heat island (UHI) is an urban area that is significantly warmer than its surrounding rural areas due to human activities. The urban area of the city of Skopje has been rising rapidly in the past decade. In this study, the effect of UHI is analyzed using Landsat 8 data in the summer period of 2014 – 2017 as a case study in Skopje. An algorithm was applied to retrieve the land surface temperature (LST) distribution from the Landsat 8 data. In addition, the correlation between land surface temperature and the normalized difference vegetation index (NDVI) and the normalized difference build-up index (NDBI) were analyzed to explore the impacts of the green land and the build-up land on the urban heat island. The results indicate that the effect of urban heat island in Skopje is located in many sub-urban areas. The negative correlation between LST and NDVI indicates that the green land can weaken the effect on urban heat island, while the positive correlation between LST and NDBI means that the built-up land can strengthen the effect of urban heat island in the study area.