This study conceptualised self‐help groups (SHGs) from the behavioural systems perspective. It adopted the grounded theory approach for data collection and analysis; and the development of structural frameworks through causal inferences. The behavioural system of the SHGs had psychological and behavioural input (interest, motivation, intention, value, belief and need), psychological and behavioural process (adaptability, receptibility and cognitive ability), psychological and behavioural output (social behaviour, psychological behaviour, economical behaviour and ecological behaviour), and environment (macroeconomic environment, policy environment, social–cultural–political environment of village, and institutional environment of the village). The psychological and behavioural input, process, and output exhibited interdependencies. The conceptual categories within them showed causal interactions. The study provided a new lens to the debate on self‐help group‐based microentrepreneurship and group dynamics. The study found the systemic approach of SHG functioning and the peer pressure mechanisms built upon psychological and behavioural characteristics.