The purpose of the study was to explore work related WhatsApp groups as knowledge sharing platforms among librarians in selected federal universities in Nigerian. The study adopted the descriptive survey design. A total of 58 librarians who received and filled questionnaire in five federal universities constituted the sample of the study. Data were collected through questionnaire while frequency counts and percentages were used to analyse the data obtained. Findings revealed that a majority of the librarians were members professional association WhatsApp group, followed by group that serves the entire library, staff union group and group created by colleagues; ICT ranked highest as area the librarians shared work related knowledge followed by job opening/vacancies and publication/research; ease of use, immediate feedback, sharing knowledge with wide audience and available always were key reasons for sharing work related knowledge via WhatsApp groups; videos, audios and texts were the major formats of sharing knowledge through work related WhatsApp groups while non-adherence to group guidelines was a major drawback to knowledge sharing via the WhatsApp groups. Adhering to guidelines by members, frequent visits to WhatsApp group platforms to keep track of shared knowledge as well as increasing WhatsApp group contact limit from the current 256 members are recommended in the light of the results of the study.