Background: This study was a descriptive research study conducted to investigate the influences of cognitive emotion regulation and social support on social anxiety among nursing students. Methods: The participants were 672 nursing department students at a university. The participants were surveyed using structured questionnaires for cognitive emotion regulation, social support, and social anxiety from March to May 2017. Results: The results showed that the absence of social conflict, rumination of cognitive emotion regulation, and social support were found to affect social anxiety; these variables predicted the social anxiety of nursing students by 27%. The social anxiety of nursing students also varied according to religion, satisfaction with their nursing major, and academic achievement. There was a positive correlation between cognitive emotion regulation and social anxiety, but a negative correlation between social support and social anxiety. Conclusions: This study was significant in demonstrating that cognitive emotion regulation and social support of nursing students are verified factors affecting social anxiety. It is necessary to consider cognitive emotion regulation and social support when developing an intervention program to reduce social anxiety in nursing students.