The study looks into the idea of employing ground granulated blast-furnace slag (GGBFS) as a partial replacement in cement mortar to reduce environmental issues associated with waste disposal. This study examines cement mortar mixes 1:3 and 1:6, replacing cement with GGBFS in partial replacements of 0, 10, 20, 30, 40, and 50%. The engineering properties of materials, such as flow and compressive strength of each mix at the 7- and 28-day curing ages, were investigated. The embodied energy (EE) for all the mixes of mortar has been computed in order to check and compare EE of conventional mortar with GGBFS incorporated mortar. This study shows that GGBFS can be used in mortar application as partial substitute for cement. The present study thus aims to determine the mortar mix which has the least EE. The study also reveals that EE of GGBFS-replaced mortar is a step toward minimal energy consumption when compared with the control mix.