<p>International altruism is crucial for promoting global stability and peaceful development. Thus, it is vital to identify factors that can enhance international altruism. Building upon the revised small-self hypothesis, we investigated whether dispositional awe affects international altruism, as well as the mediating roles of self-transcendence and identity with all humanity (IWAH), in different cultural contexts. A total of 780 participants from China (<i>N</i> = 497) and the US (<i>N</i> = 283) took part in this study. The multiple mediation model revealed that dispositional awe was positively associated with international altruism in both countries. Furthermore, in the Chinese sample, dispositional awe indirectly affected international altruism through the mediating roles of self-transcendence and IWAH, both parallelly and sequentially. By contrast, in the US sample, dispositional awe indirectly affected international altruism through the independent mediating effect of IWAH, and the sequential mediating effects of self-transcendence and IWAH. Overall, these findings contribute to understanding the potential factors of international altruism across cultures from a unique perspective of positive psychology and provide practical insights for enhancing intergroup relations.</p>