Insects are the most speciose group of animals and play a central role in ecosystem processes and functioning, yet they are often overlooked in conservation studies. Many studies have reported a dramatic decline of insects globally, where climate change is considered a profound threat; however, how climate change is impacting tropical insects is largely unknown, given most studies are from the temperate region. Here, by considering Bangladeshi butterflies as a case study, I developed climatic suitability maps for 242 species and compared the suitability under current and future (2081-2100) climatic conditions. Overall, the projected future climate could impact 241 of 242 butterfly species (except for Spindasis elima), where 42% species could experience range contraction. Alarmingly, the impact could be significantly more severe among threatened species. While the direction of shift in habitat suitability could be multidimensional, about 65% of species might move north. While the suitability range could expand for about 58%, most threatened species (58%) could experience range contraction. The mean elevation of the suitable habitat could increase by 238%, and again the situation could be more severe for the threatened butterflies (from 42m to 108m). The niche-overlap analysis indicates that about 54% of the realised niche could be altered. Although there might be no significant association between the shift in habitat suitability along the elevational gradient, migratory species could experience a more significant shift than non-migrants. I show that climate change could have a severe impact on Bangladeshi butterflies – depending on Socio-Economic Pathways (ssps), the future climatic condition could be unsuitable for 2 (ssp126) – 34% (ssp585) species. To mitigate insect decline globally, and therefore, to meet the Post 2020 Biodiversity Framework targets, I urge immediate detection of climate change impact on tropical insects and developing effective conservation strategies.