The use of Relationship, Information and Communication Technologies (RICTs) has changed the way in which university students interact and relate to each other, giving rise to both positive and negative experiences, in which they must deal with risky cyber-behavior. Cyberostracism is a form of social exclusion in the virtual space that leads to feelings of social anxiety and that can occur in university students, causing harmful consequences. However, it has not been sufficiently explored whether this feeling can be related to an increase of Internet use due to perceived online exclusion. Focusing on this, the aim of this paper is to find out the association between cyber-ostracism and social anxiety, as well as the possible indirect effect of Internet use. A total of 1605 students from different Spanish universities participated in the study, aged between 17 and 25 years old (M = 19.59, SD = 1.75), where 66.3% were women, 31.7% men and 2% did not indicate their gender. The Internet-Related Experiences Scale (CERI), the Social Anxiety Scale for Adolescents (SAS-A) and the Cyberostracism Experience Scale for Adolescents were used. Statistical analyses included Student's t-test and mediation analysis with the macro PROCESS. Results indicated that men showed higher levels of cyber-ostracism, while women scored higher levels of social anxiety. Cyberostracism was related with a higher social anxiety among university students, associated to Internet use. We discuss how this form of virtual ostracism continues to increase and how it affects students of higher education. We also discuss how Internet use may increase the risk of social anxiety in victims of cyber-ostracism. These findings have important implications for future prevention and intervention programs.