AbstractOver-adaptation is a common personality trait in Japan. Previous studies have identified “responsible over-adaptation,” according to which various problems, such as internal maladaptation, are caused by excessively adaptive behavior. However, several related issues regarding responsible over-adaptation remain to be addressed, one of which is why individuals tend to prioritize others too much. This study investigates the characteristics of responsible over-adaptation in relation toShitsutaikansho and emotional empathy. A web-based survey was conducted in November 2022 with 325 participants aged 15–29 years (M = 23.42, SD = 3.95). Analyzing using RStudio (Version 1.4.1717) statistical software. All factors of responsible over-adaptation andShitsutaikansho showed a weak positive correlation. Furthermore, the two factors related to external adaptive behavior and emotional empathy showed a moderately strong positive correlation, while a weak positive correlation was found between over-adaptation harm and emotional empathy. Furthermore, cluster analysis showed thatShitsutaikansho and emotional empathy were higher in the responsible over-adaptation group than in the other groups. Our results suggest that responsible over-adaptation is characterized by two features—Shitsutaikansho and emotional empathy—which lead to an excessive preference for others over oneself. Difficulty in noticing bodily sensations may enable “over-adaptive behavior,” masking fatigue and physical symptoms and resulting in maladaptation.Keywords: responsible over-adaptation, Shitsutaikansho , emotional empathy, adaptive behavior, altruistic behavior