Conflict is inevitable in all organizations, and the university being a center of learning, with diverse needs is not left out. The study examined the different conflicts occurring in the Nigerian South-West federal universities and their impact on staff effectiveness. The academic and the non-academic staff of the three South-West federal universities in Nigeria constituted the population for the study from which 1385 participants were selected as samples. The survey research design was adopted for the study. The stratified and simple random sampling techniques were used to select the sample from the three unions in the selected universities. Two sets of research instrument namely: Conflict and Staff Effectiveness Questionnaire (CSEQ) and an interview schedule were used for data collection. Three research questions and two research hypotheses were answered and tested in the study. The research questions were answered using descriptive statistics of percentages, frequencies, and means while the hypotheses were tested using inferential statistics of T-Test and Pearson Product Moment Correlation. The findings of the study are that conflicts were significantly related to staff effectiveness and that the effectiveness of the academic staff was affected more than that of the non-academic staff during conflicts. The study recommended the need for the Nigerian South-West federal universities and the federal government to embark on morale booster programs for the university staff.