Abstract Purpose: In this research, we want to study staff social participation, and its related factors, amongst librarians of Tabriz public libraries. Methodology: This is a survey. The research population includes all 155 librarians from Tabriz public libraries. Data was collected using a researcher- made questionnaire. The validity of the questionnaire is confirmed by experts, and its reliability was measured by Cronbach's alpha. Data analysis was performed using the SPSS software package. Findings: Results show that the level of social participation amongst the staff of Tabriz public libraries is at a medium level. Findings also show an inverse correlation between social participation and the two variables of "interpersonal trust" and "social alienation" , but a direct correlation between social participation and "reward motives". There is no statistical correlation between "institutional trust" and "the socio-economic status of the librarians" . There is a significant correlation between social participation and the basic variables such as gender so that the social participation of male librarians is more prevalent than that of female librarians. All in all, a combination of individual and social elements is involved in the construction of the theoretical model, based on behavior and participation theories. Based on these findings, the significance of social participation is strongly recognized by the research community. The clarification coefficient in regression equation is on a low level, so it seems that we need some other illustrative variables to explain the levels of social participation. We should also take the analysis level further than micro, and macro levels, and consider effective macro variables related to social participation from outside library organizations. Originality/value: By paying attention to the importance of social participation in the cultural, social and economic development of a society, library staff due to their high levels of communication with large groups of students, teachers, scholars and the general public, can play a key role in this regard. This study is the first of this kind of research.