Despite critical thinking (CT) being a focal point in higher education, gaps remain in comprehending the psychological factors underlying the formation of CT disposition and its transition into actual CT behavior. To address the gap, we introduce a behavioral perspective to CT research that is based upon the Theory of Planned Behavior (TPB). We first identify the theoretical cohesion between CT and TPB, conceptualizing CT disposition as "behavioral intention" and performing CT action as "behavior." We identify the three TPB-based psychological antecedents to CT disposition, namely, "attitude," "perceived behavioral control," and "subjective norms." To operationalize CT disposition, we adopt the constructs of "critical openness" and "reflective skepticism." The theoretical propositions are then empirically validated through a survey of 363 undergraduates in Singapore. Results indicate significant relationships between the antecedents and CT dispositions, with a partial effect for subjective norms. Particularly, subjective norms significantly enhance reflective skepticism but have a minimal effect on critical openness. However, a gap between students' CT disposition and students' performance is observed. The insights gained from the findings will be useful in guiding the development of psychological interventions for CT development.