This study aimed to evaluate the effectiveness of a social skills training program (SST) in reducing social anxiety. The participants were 32 university students with significant social anxiety symptoms that completed the “Social Anxiety Questionnaire for Adults” (SAQ-A30) and the “Liebowitz Social Anxiety Scale-Self-report” (LSAS-SR). The 10-session intervention program addressed issues such as anxiety management, assertiveness, relaxation techniques, interpersonal relations, public speaking and expression of feelings. Mean differences and effect size showed that there was a significant change in the post-treatment scores on the two measures compared with the pretreatment ones, both globally (SAQ-A30 and LSAS-SR) and in the five dimensions of the SAQ-A30. These data further support the SAQ-A30 sensitivity to measure changes over time and the validity of this new measure of social anxiety. We conclude that the SST program is highly effective in reducing social anxiety of university students and that the SAQ-A30 is an appropriate measure for assessing social anxiety disorder.