Studies on the theory of mind (TOM) and alexithymia in borderline personality disorder (BPD) have yieldedinconsistent results. Also, the relationship between TOM abilities and alexithymia facets as two domains of socialcognition has not been studied in BPD. This study aimed to fill this gap. Participants were 50 outpatients withBPD and 50 age and gender-matched healthy controls. Assessments performed using Reading the Mind in EyesTask (RMET), Toronto Alexithymia Scale (TAS-20), Faux Pas Task (FPT), and Digit Span subtest of WechslerAdult Intelligence Scale. Results showed that BPD patients scored lower on overall FPT (p < .001) and itscognitive (p < .001) and affective TOM (p < .001) subtests but were comparable with healthy controls in emotionrecognition ability assessed by RMET (p = .241). The BPD group also scored significantly lower in overallalexithymia (p < .001) and subscales of difficulty identifying feelings (DIF; p < .001) and difficulty describingemotions (DDF; p = .001). However, they performed similarly to the healthy control group in externally orientedthinking (EOT; p = .164). Correlation analysis revealed a significant negative correlation between EOT andRMET in the BPD group (r = − 0.33, p < .05). No association, however, was found between FPT and RMET. Thisstudy suggests that BPD patients are impaired in the complex TOM abilities and have lower self-awareness ofemotions, but their recognition of others’ emotions is intact. Also, the results demonstrate that a heightened levelof EOT is associated with difficulties in facial emotion recognition in BPD patients.