This paper examines utilisation of Web 2.0 tools for effective library services by librarians in University Libraries in Southwest Nigeria. Two hundred and three (203) copies which are (94%) were duly completed and found usable for this study. Questionnaire was used as instrument for data collection. The questionnaire was on types of Web 2.0 tools available, services available and influence of Web 2.0 use. Data obtained was analysed using descriptive statistics such as frequencies, percentages, mean, and standard deviation. Findings of the study revealed that 54% respondents indicated Youtube as the major type of Web 2.0 tools, followed by Facebook 50.5% and Twitter with 48% by librarians in University Libraries in Southwest Nigeria. Some of the recommendations were that Libraries management should provide internet access to staff and users of their libraries, and due to the dynamic nature of Web 2.0 tools, librarians need to keep themselves abreast of the new technology and remain relevant on their duties.
Keywords: Librarians, Library Services, Utilisation., university libraries, web 2.0 tools