Awe is a self-transcendent emotion that can diminish one’s focus on the self and serves as an important motivator of commitment to social collectives. However, the influence of awe on ecological behavior is not clear. This study examines the relationships between people’s feeling of awe, their connectedness to nature, and ecological behavior. Three experiments tested the effect of awe on ecological behaviors including mediation tests. Compared with participants in the control condition, participants in the awe condition were more inclined to behave ecologically (Study 1 and 2) and reported a higher feeling of connectedness to nature (Study 2). Moreover, the relationship between awe and ecological behavior was mediated by connectedness to nature (Study 3). These findings indicate that awe helps broaden the self-concept by including nature and increase connectedness to nature, which in turn lead to ecological behavior. They also highlight the significance of connectedness in explaining why awe increases ecological behavior.