Objective: Behavioral inhibition plays a key role in animal stress research and developmental research in children. Therefore, we examined the robustness of our multifaceted model of adult social inhibition that comprises behavioral inhibition, interpersonal sensitivity, and social withdrawal components. Method: A total of 899 adults completed the 15-item Social Inhibition Questionnaire (SIQ15) and measures of emotional distress. Confirmatory Factor Analysis (CFA), reliability estimates, and correlational and second-order factor analyses were used to examine the robustness of our model. Results: CFA (RMSEA=.052; NFI=0.938; CFI=0.957) and Cronbach's α estimates ≥.87 confirmed the robustness of our multi-facet social inhibition model based on three correlated inhibition, sensitivity, and withdrawal factors in 560 adults from the general population and in 194 undergraduate students. Inhibition, sensitivity, and withdrawal were stable over time (3-month test-retest correlations ≥.78), and were closely related to the Gest Behavioral Inhibition and PID-5 Withdrawal measures in a clinical sample of 145 cardiac patients. Of note, male cardiac patients reported more inhibition and withdrawal than female patients. Across samples, social inhibition was distinctly different from negative affectivity. Conclusions: Our 3-facet model of inhibition, sensitivity and withdrawal was robust across samples, and may promote research on adult social inhibition in population-based and clinical studies.