This study examined how cognitive and motivational factors relate to individuals’ reasoning about climate change and sustainability. Specifically, we investigated whether self-efficacy, interest, and confidence in accomplishing environmental sustainability tasks are associated with plausibility judgments, climate change knowledge, and reasoning directionality. A sample of 503 U.S. adults completed measures assessing these constructs. Structural equation modeling showed that interest, self-efficacy, and confidence were positively associated with plausibility judgments, which in turn related to higher levels of climate change knowledge and accuracy-directed reasoning. Participants demonstrating accuracy-directed reasoning exhibited enhanced self-efficacy, greater interest, higher knowledge, and stronger plausibility judgments compared to those engaging in desired outcome-directed reasoning. These findings suggest that self-efficacy, interest, and critical evaluation skills are meaningfully related with epistemic engagement and scientifically grounded reasoning, and may be relevant targets for future efforts at supporting sustainability-oriented action and decision-making.