AbstractThe objective of the study is to design and develop an Urban Heat Island e-module for high school students in Surakarta using the Borg and Gall model of Design and Development Research (DDR). The research method consisted of need analysis, design and development, and implementation and evaluation of the e-module_s effectiveness for students_ achievement, collaboration skills, and Urban Heat Island (UHI) awareness. The need analysis samples employed multistage sampling. The design and development phase used the Fuzzy Delphi method to validate the e-modules involving 11 experts in Geography Education and the UHI field. The research design in the implementation and evaluation phase used a quasi-experimental approach where a sample of schools was tested using stratified random sampling. The research results reveal a threat of UHI in Surakarta, as indicated by the increased Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI). Additionally, the result shows that .....