This study sought to investigate the motivating factors for Georgia Extension Agents to participate in supplemental professional development opportunities beyond those required for their current role. The study was based on Ajzen's theory of planned behavior, focusing on intention, attitude, subjective norm, and perceived behavioral control. The correlation analysis results indicated that attitudes and perceived behavioral control are statistically significant and positively correlated with intention, suggesting that favorable attitudes and high confidence in completing professional development programs increase the participation rate. Moreover, multiple regression analysis revealed that attitudes and perceived behavioral control collectively accounted for 48.6% of the variance in intention, highlighting the effects of both external environmental influences and personal motivation in affecting individuals' intention to participate in supplemental professional development programs.