This study investigated the relative contributions of demographic characteristics influencing utilization of John Harris Library, University of Benin (UNIBEN) by undergraduate students. A four point likert scale instrument with 35 questions was used to collect data. Seven questions were on demographics, ten questions on utilization of the library while 18 questions were on factors influencing utilization of the library. Respondents consist of 243 undergraduates at different levels of their studies. Data collected were analyzed using frequency distribution, percentage, mean, Pearson Product Moment Correlation, regression analysis (ANOVA). Results revealed that there is high and significant level of utilization of the library among the undergraduate students of the university. Demographic characteristics (academic discipline, level of study, gender and age) made collective significant contribution to the use of the library. Level of study made significant relative contribution towards utilization of the library. Efforts should be put in place by the managers of the library to sustain this result and improve on it.