Year of study and the level of social interaction anxiety may be related to several outcomes associated to the academic performance of students. This study thus set out to investigate possible differences in social interaction anxiety based on the years of study of students in the University of Lagos. This study adopted a cross sectional survey research design as data was obtained utilising self-report measures from students sampled from four different levels of study. 142 (54%) were male students while 121 (46%) were female students. The age of participants was between 16 years and 30 years. The number of participants across the levels indicate that 96 (36.7%), 80 (30.3%), 47 (17.8%) and 40 (15.2%) students represented 100, 200 300 and 400 level students respectively from six faculties in the University of Lagos. Two hypotheses were tested to explain students’ year of study and their social interaction anxiety. The Social Interaction Anxiety Scale (SIAS) was administered to the participants. Thus, one-way ANOVA statistic was conducted to test the hypotheses. The results reveal statistical differences in social interaction anxiety exhibited by 100, 200, 300 and 400 level participants (F(3, 269, = 2.969, P<.05). The results were discussed in relation to the achievement of social cohesion among undergraduate students.