The present study aimed to investigate the relationship between the behavioral inhibition/activation systems and alexithymia with social anxiety among female university students. In a correlational design, a sample of 281 female students from the Islamic Azad University, Bojnourd (a city in Iran), was selected during the 2023-2024 academic year using multistage cluster sampling. Data were collected using the Behavioral Inhibition System/Behavioral Activation System Questionnaire (BIS/BAS), the Toronto Alexithymia Scale (TAS), and the Social Anxiety Scale (SAS). The results indicated a significant positive relationship between behavioral inhibition and alexithymia with social anxiety (P < 0.01). The regression analysis revealed that behavioral inhibition (β = 0.26) and alexithymia (β = 0.29) were positive predictors of social anxiety among female university students. However, behavioral activation was not able to predict the criterion variable (P > 0.01). Accordingly, interventions aimed at reducing social anxiety in female students should focus on decreasing behavioral inhibition and alexithymia.