This article explores the interplay between personality traits, particularly the Big Five model, and the Theory of Planned Behavior (TPB) in shaping individual investment decisions in mutual funds. Utilizing the TPB's framework, the study examines attitudes, subjective norms, and perceived control, linking them to investor intentions. Focusing on India's growing mutual fund industry, the article highlights key industry metrics, indicating robust growth in assets under management and retail participation. Comparisons with developed countries underscore India's untapped potential in mutual fund investments. The research delves into the determinants of investment decisions, considering rationality, socioeconomic factors, and the impact of personality traits. Theoretical frameworks and literature synthesis support the proposed behavior intention model. The findings emphasize the vital role of personality, particularly openness to experience, in influencing investment behavior. In conclusion, the study contributes insights for asset management companies in tailoring schemes to align with investor commonalities. Keywords: Investor, personality traits, Theory of Planned Behavior, Mutual Funds investment