This study investigated information retrieval tools and library environment as correlates of library utilization by students of Rivers State University, Port Harcourt. Three research questions were posed and two hypotheses were formulated for the study. The study adopted a correlational design. The population of the study consisted of 682 registered undergraduate library users out of which a sample of 227 was drawn using YaroYamene’s statistical formula. The instrument used for data collection was researcher-made rating scale. The data collected for the research questions were analysed using the Pearson Product Moment Correlation (PPMC) and hypotheses tested at 0.05 level of significance using t-test. The result revealed that, students make use of the various information resources to a high extent; information retrieval tools are provided in the library to a high extent, there is a very strong and positive relationship between information retrieval tools available and students’ use of the library, which is also significant and a strong, positive and significant relationship exist between the library environment and students’ use of the library. It was recommended that students should be sensitized more on the use of periodicals and fiction for relaxation; even though the relationship between retrieval tools and use is significant, there is still need for students to be sensitized on how to use the library through adequate orientation on information retrieval tools. University management should ensure that the good library environment be maintained and sustained.