Climate change poses significant threats to biodiversity, particularly affecting sensitive indicator species such as butterflies. The semi-arid region of Sikar, Rajasthan, has experienced notable climatic shifts over recent decades, potentially impacting local butterfly populations. This study investigates the impact of climate change on butterfly diversity in Sikar district, examining species composition, abundance patterns, and distributional shifts in relation to changing climatic variables. Butterfly surveys were conducted across four distinct seasons from January 2022 to December 2023 at twelve selected sites representing varied habitats. Standard transect methods were employed, with simultaneous recording of microclimate data. Historical climate data (1990-2023) were analyzed to identify long-term trends. Species diversity was assessed using Shannon-Wiener and Simpson indices, while climate-diversity relationships were examined through canonical correspondence analysis. A total of 87 butterfly species belonging to 6 families were recorded, with Nymphalidae (28 species) being the most diverse. Significant positive correlations were observed between temperature increase and reduced species richness (r = -0.67, p < 0.01). Summer temperatures have increased by 1.8°C over three decades, while rainfall patterns showed increased variability. Thermophilic species showed range expansion, while mesophilic species exhibited population declines averaging 34%. Five species previously recorded in historical surveys were not encountered during the study period. Climate change is significantly affecting butterfly diversity in Sikar, with evidence of species turnover, phenological shifts, and altered community composition. Conservation strategies must incorporate climate adaptation measures to preserve butterfly diversity in this semi-arid ecosystem.