Social anxiety disorder (SAD) is prevalent among university students, yet data on its severity among foreign-born international undergraduate students in Türkiye remains limited. This study aims to determine the prevalence of SAD and its associated factors within this population. A cross-sectional study was conducted using a Google Form survey distributed across various universities from September 17, 2023, to February 1, 2024. The survey comprised two sections: sociodemographic information and 17 items of the Social Phobia Inventory (SPIN), which measures the frequency and intensity of social anxiety symptoms. Data analysis included descriptive statistics and inferential analysis, multiple regression, and binomial logistic regression. Out of 506 participants, 455 were included in the study. Results revealed that 39.1% exhibited no or very mild symptoms of SAD, while 23.7% experienced mild symptoms, 21.3% faced moderate symptoms, and 11.6% and 4.2% presented with severe to very severe symptoms, respectively. Factors such as gender (p < 0.0001), previous academic failures (p = 0.013), family history of mental health issues (p = 0.009), exercise frequency (p < 0.0001), and perceptions of relationships with classmates (p < 0.0001) were significantly associated with SAD. Females showed a higher probability of SAD compared to males (OR = 1.976). Individuals engaging in over 90 minutes of exercise per week were less likely to have SAD (OR = 0.383), and occasional smokers had a lower risk of SAD compared to non-smokers (OR = 0.422). Our study uncovered a notably elevated prevalence of Social Anxiety Disorder (SAD) among foreign-born undergraduate students in Türkiye. Factors such as being female, having a family history of mental illnesses, studying in a stressful environment, experiencing academic failure, and engaging in less frequent exercise were associated with noticeable symptoms of SAD. These findings emphasize the urgent need for heightened efforts in recognizing and addressing SAD within this population.