The Teesta River basin, located at the foothills of the Himalayas, frequently experiences severe weather conditions that significantly affect rural livelihoods. The purpose of this research was to examine the local population’s vulnerability to the effects of climate change and their adaptation plans to cope with these changes in the Teesta River basin in Bangladesh. By using a proportional random sample method, a total of 180 individuals were chosen for the study. Three important characteristics were included in the research to assess household vulnerability: exposure, sensitivity, and adaptive capability. Meteorological data analysis indicated a rising trend in both maximum and minimum temperatures, while rainfall and flooding have been decreasing. Most respondents reported that over the past 10–20 years, temperatures, heat intensity, and drought conditions have increased, whereas rainfall and flood occurrences have declined. Dimla Upazila is notably vulnerable in terms of food security, agriculture, health, and adaptation capacity, as indicated by the Livelihood Vulnerability Index (LVI). In contrast, Hatibandha Upazila was identified as being more susceptible to extreme climate events and possessed a restricted level of self-efficacy in adaptation strategies. Households in Hatibandha were more exposed and sensitive to climate change, making them the most vulnerable due to their lower ability to adapt. Overall, the study suggests that Hatibandha communities face greater climate-related risks than those in Dimla. The majority of respondents said they used adaptation techniques such as community-based maize farming, household gardening on raised soil, and irrigation under the Teesta Barrage Project to deal with climate change. These findings can help policymakers develop targeted strategies to reduce vulnerability and strengthen the resilience of at-risk communities in Bangladesh.