Abstract The study dwells on application of interpersonal communication in reference and information services in university libraries. Four research questions in line with the objective of the study were formulated to guide the study. The study adopted descriptive survey research design with the total population of 1,116. The sample size of the study was 330 students while 16 reference staff were studied without sampling due to their manageable size. Data was collected using questionnaire. A total number of 346 copies of questionnaire distributed were correctly filled and returned by the respondents who comprised entire reference staff, postgraduates and undergraduates’ library users of university of Nigeria, Nsukka; Michael Okpara University of Agriculture, Umudike and Nnamdi Azikiwe University, Awka. Data were analyzed using mean scores. Result shows that face to face communication, simplified language, customer relations were among the major interpersonal communication patterns in reference services in university libraries. It was found that interpersonal communication to a great extent contributes to effective reference and information services in university libraries by making exchange of message easier, and enhancing understanding of users information needs. Major hindrances to effective application of interpersonal communication in reference and information services include inability to frame queries correctly, lack of adequate listening skills, stereotype and interiority complex of librarians, etc. Strategies for enhancing interpersonal communication include carefully listening, right framing of reference queries and many more. The study recommended effective user education program while reference staff should be well educated to be able to communicate effectively with users of different background.