With university students from Japan as participants, the current study was undertaken to examine the hypothesis that gratitude for and/or regret toward nature positively relate to proenvironmental intent. On the basis of preliminary studies, we constructed a questionnaire containing scales aimed at measuring gratitude, regret, and general feelings or impressions about nature, as well as a scale of proenvironmental intent, which was adapted from frequently-used scales of proenvironmental attitude. The partial regression coefficients of gratitude and regret on proenvironmental intent when general feelings towards nature were controlled suggested that only regret had a significant partial correlation with proenvironmental intent. A complementary study using scenarios about environmental behaviors confirmed the significant contribution of regret toward nature to proenvironmental intent in Japanese students.