Climate change increases the vulnerability of agricultural sector due to the increasing threat from pest attacks. Mitigation of a threat that results from climate change requires adaptation strategies. This study investigates farmers’ willingness to participate in the process of climate change adaptation in Yogyakarta, Indonesia; particularly in facing the increasing risk of pest attacks. Using a logistic regression model, we tested the impacts of social capital on farmers’ willingness to participate. The results showed that 70% of farmers were willing to contribute financially to the adaptation process. This participation was positively correlated with high social capital, which consists of high level of trust, community engagement, and personal relations with people in other villages. This study contributes to the literature by highlighting the potential roles of social capital in the process of climate change adaptation in agricultural sector. 1. Introduction Climate change is indicated by extreme weather, unpredictable temperature, and fluctuating rainfall. Studies have shown that climate change may reduce a country’s overall agro-economy performance (Fischer et al., 2005; Georgescu et al., 2011; Lobell et al., 2008); hence may threaten food security (Krishnamurthy et al., 2009, 2014; Richardson et al., 2018). In South East Asia, climate vulnerability may decrease the production of grains and maize by approximately 10% (IPCC-TGICA, 2007). In Indonesia, climate change causes water shortage, lowers soil moisture, decreases soil fertility, and increases evaporation and precipitation (Measey, 2010). Overall, this poses a threat to food security. Research shows that Indonesian paddy production was reduced by about 25% due to climate change in 2014 (Fadhliani, 2016). Climate change could also increase sea levels and flood rice and shrimp farms (Measey, 2010). Saptutyningsih and Ma’ruf (2016) have shown that farms in Yogyakarta, Indonesia, were highly affected by climate change e.g. flood and drought that could damage agricultural lands and pest attacks on crops (Baehaki and Widiarta, 2009; Romadhon, 2007; BBPOPT, 2015; Deptan, 2009) that may have a major cause of production failure (see Fig. 1). Climate change affects social and economic sustainability of the agricultural sector, both directly and indirectly.