Recent research indicates that pro-environmental behavior may be driven by concerns about one’s moral identity. Using identification with the environmentalist movement Fridays for Future, this paper develops and empirically tests a straightforward model of self-signaling. We assume that pro-environmental behavior, here taking the train rather than the plane for a journey, serves as a means of self signaling. On the basis of a large-scale survey experiment with an incentivized choice, we find evidence that respondents who receive an identity prime in the form of a reminder of their previously stated attitude towards Fridays for Future are more likely to behave in line with the movement’s moral principles in that they take the train. Moreover, respondents who are less secure about their identification with the movement are also more likely to opt for the train. Our explanation of these outcomes is that individuals attempt to avoid cognitive dissonance by choosing the more environmentally benign alternative. Our results suggest that pro-environmental behavior may be enhanced by appealing to an individual’s self-image.