Empathy and interpersonal skills are components of mentalizing and competencies that social work students are expected to acquire during training. Yet limited scientific data exists on factors that influence their attainment. This study was conducted to examine how social work training and individual attachment style are associated with two aspects of mentalization: reading non-verbal communication and reflective thinking. Using a cross-sectional design, 63 social work students participated in this internet-based study. Results showed that regardless of the amount of exposure to social work training, students with an insecure style of attachment had significant deficits in their ability to accurately identify non-verbal expression of thoughts and emotions. Additional results showed that social work training significantly influenced the use of higher order reflective thinking. These findings suggest that students bring an internal relational template with them that is associated with one's capacity for mentalization, specifically accurately interpreting interpersonal communication.