The present study aimed to investigate the mediating role of the Dark Triad in the relationship between behavioral inhibition and activation systems and experiential avoidance. The research design was correlational and employed structural equation modeling. A total of 770 graduate students from the Islamic Azad University, Science and Research Branch (Tehran, Iran), were selected through convenience sampling. Data collection was conducted using the Multidimensional Experiential Avoidance Questionnaire (MEAQ), the Behavioral Inhibition System/Behavioral Activation System Questionnaire (BIS/BAS), and the Dark Triad Dirty Dozen (DTDD). Data analysis was performed using partial least squares structural equation modeling (PLS-SEM). The findings revealed that the Dark Triad plays a significant mediating role in the relationship between behavioral inhibition and activation systems and experiential avoidance (P < 0.05). Moreover, behavioral activation and inhibition systems, along with the Dark Triad, exert a significant direct influence on experiential avoidance (P < 0.05). These results suggest that brain system activity, shaped by individual personality traits, impacts students' avoidance of challenging situations. These findings contribute to a more comprehensive theoretical understanding of experiential avoidance.