AbstractEnvironmental policies frequently assume that people only act to help the environment if such behavior is in their self‐interest. A growing amount of literature, however, shows that people also derive positive emotional benefits or “warm‐glow from acting green. Yet, it remains unclear to what extent this motivation is derived from classical accounts of altruistic concern. In the current study, we leveraged a prospective design of a unique sample (N1 = 341, N2 = 251) of customers who subscribe to a local sustainable food store. We measured altruistic and green warm‐glow at T1 and predicted to what extent such prospective warm‐glow predicted a range of self‐reported conservation behaviors 4 weeks later (T2). Results suggest that the anticipated warm‐glow from helping other people did not significantly predict green intentions nor green behavior despite being highly correlated with green warm‐glow. In fact, only green warm‐glow significantly predicted conservation behavior over time. These findings are important because they elucidate a basic differential motivation between helping other people versus protecting the planet. This differentiation is critical to the design of effective conservation interventions.