Background and aims: Dysregulation in instrumental control systems is implicated in compulsivity, a transdiagnostic construct proposed to underlie diverse maladaptive behaviors. While habit formation in reward-based learning is well-characterized, its role in avoidance learning remains less understood. Habitual avoidance may contribute to compulsive symptoms by impairing emotion regulation, a wellestablished correlate of compulsivity. To define these mechanisms, this study examined negative emotionality as a pathway linking habitual avoidance to compulsive behaviors. Methods: Five hundred adults completed the Avoidance Dynamics Task (ADT), a novel online-administered aversive devaluation paradigm assessing avoidance learning and habit strength, alongside validated self-report measures of compulsive behaviors (alcohol use, binge eating, binge watching, gambling, obsessivecompulsive symptoms) and internalizing symptoms (depression, anxiety). Mediation analysis tested whether internalizing symptoms accounted for associations between habitual avoidance and compulsive behavior severity. Results: Habitual avoidance, indexed by perseverative responses to devalued threat versus control cues (t = 3.5, p = .002), showed small-to-moderate positive associations with avoidance urges (ƒp = .28, p < .001), regulatory control deficits (ƒƒp = .17, p < .001), and internalizing symptoms (ƒb =  .15, p 5 .004). Internalizing symptoms fully mediated associations with all compulsive behaviors (b's = .05-.16, all p <= .01). Impaired avoidance learning was modestly associated with greater alcohol use (b = -.12, p = .03) and gambling (b = -.15, p = .02) severity. Exploratory analyses showed distinct avoidance patterns mapped onto cognitive (preoccupation, urges) versus behavioral (control, frequency) components of alcohol-related compulsivity. Conclusion: Habitual avoidance may represent a transdiagnostic behavioral marker of compulsivity. These findings underscore distinct vulnerability pathways across compulsive domains and support the use of remote tasks to phenotype maladaptive avoidance and related emotional dysregulation.  Kulcsszavak: addiction, avoidance, compulsivity, habit, negative emotionality, transdiagnostic