Climate change has resulted in the increase of surface temperatures, which has significantly affected water availability, disrupting economic development and quality of life. Thus, the application of drought index and water scarcity for analysis is essential, as they accurately estimate the impact of water availability. This study quantifies drought and water scarcity using SPEI and WEI+, respectively, and investigates their interrelationship in the Langat River Basin. The results revealed a strong positive correlation between the drought and water scarcity index, with correlation coefficients of 0.9677, 0.9545, and 0.9633 for SPEI-3, SPEI-6, and SPEI-12, respectively. The frequency analysis of the drought index showed 54 occurrences for SPEI-3, 58 for SPEI-6, and 61 for SPEI-12. Meanwhile, the water scarcity index was quantified for the period from 2015 to 2018, yielding values of 2.60 × 10⁻³ in 2015, 3.81 × 10⁻³ in 2016, 3.39 × 10⁻³ in 2017, and 3.68 × 10⁻³ in 2018. Overall, these findings provide valuable insights and form a robust basis for developing effective mitigation strategies and informed decision-making in water supply planning and river basin management, thereby reducing potential adverse impacts on water resources.