This chapter discusses the main limitations of the study and outlines directions for future research. Key limitations include reliance on ESG data from a single provider, which may introduce size and regional biases, and the limited additional explanatory power of the behavioural three-factor model beyond the market factor. Data and sample constraints may also affect the generalizability of the findings. Future research is encouraged to incorporate multiple ESG data sources, further examine the role of arbitrage frictions, and explore how regulatory and cultural differences, as well as evolving global sustainability reporting standards, influence behavioural biases in ESG investing.