PurposeThis study aims to investigate the behavioural factors that affect individual investment decisions among Generation Y in Malaysia.Design/methodology/approachFive human behaviours such as trait anger, trait anxiety, overconfidence, herding factor and self-monitoring have been examined using a sample of 502 respondents.FindingsThe results reveal that trait anxiety and overconfidence are negatively related to investment decisions while self-monitoring is positively associated. Trait anger and herding behaviour do not significantly affect investment decision. The results also show that investment decision-making is significantly distinct when examined by gender, employment status and income allocation. Among these three variables, the result shows that only self-employed individuals and those in the 5–10 per cent income allocation group are marginally positive vis-à-vis investment decision-making.Originality/valueThe outcomes of this study will expand investors' knowledge about the financial decision-making process.