This study tried to understand the mountainous households’ perception of climate change and its impacts on food security in the Lamjung district of Nepal. The study attempted to find out changes in households food security and daily activities in the face of climate change for the last twenty years. The study started with the 150 household surveys along with participatory rural appraisal to understand the climate change perception of local people and its impact on dimensions of food security. Households expressed different levels of perception in terms of climate change on food security. The result shows that most of the mountainous households experienced increased temperature, less rainfall in winter, an increasing number of natural disasters and the emergence of insects for the last twenty years. They perceived the role of climate change in decreased crop production, decreased dairy products and increased household work. The situation of food security is likely to be more vulnerable to climate change in the future. It was also observed that households have been using different autonomous adaptation measures, such as high yielding crop varieties, enhanced irrigation systems and fertilizers, to cope with the changing climate. Finally, the study recommended policy instruments to enhance food security in the mountainous region amidst changing climate.