Adaptation to the negative impacts of climate changes by farmers is often autonomous. Perception on climate change is an important aspect that determines the coping strategies adapted by farmers to the impacts of climate change. Therefore, identifying the perception of smallholder farmers on climate change is important to understand their adaptation strategies to climate change and support them in their initiatives. Therefore, this study was conducted to identify the perceptions and adaptations of smallholder farmers to climate change, and to study the factors influencing the climate change perceptions and adaptations in Hakwatuna-oya Major Irrigation Scheme in the Kurunegala district of Sri Lanka. Primary and secondary data were collected by surveying 298 households from all the 17 GN divisions in the scheme. Data were filtered based on the size of land cultivated (less than 2 ac.) and the main income source (agricultural) to identify smallholder farmers. Statistical analysis was performed using SPSS software. Sixty one percent (61%) of the households in Hakwatuna-oya scheme are smallholder farmers. About 89% of the smallholder farmers have observed that climate change in terms of increased temperature, decreased rainfall, increased extreme rainfall events, increased drought incidents or unpredictability of rainfall have occurred over the past 10 years. About 84% of the smallholder farmers have identified crop failure as the main impact of climate change and 61% have carried some form of adaptation measures to climate change impacts. Perception has significant correlation with adaptation of smallholder farmer to climate change impacts. Perception and adaptations to climate change have significant correlations with socioeconomic, demographic and government interventions. Therefore, any action towards building adaptive capacity and resilience to climate change impacts must consider these aspects for the interventions to be effective.