People who work in helping professions that involve interacting with people—especially teachers could be more vulnerable to mental discomfort due to stress. Thus, this study examined the relationship between occupational stress and academic staff productivity in public tertiary educational institutions in Lagos State. Two hypotheses (tested at 0.05 level of significance). With the study’s foundation anchored on Transactional Theory of Stress and Effort-Reward Imbalance Theory (ERI) in which correlational and descriptive research designs were adopted, its population comprised all academic staff in public tertiary educational institutions in Lagos State. The sample size was 700. Questionnaire was used to collect data after ensuring its validity and establishing their reliability using test-retest method. This is the ‘Occupational Stress Questionnaire for Teachers (OSQT) (r = 0.94). In addition, Records observation was used to obtain examination results from the tertiary educational institutions sampled. Analysis was carried out using inferential statistics of Pearson’s Product-Moment Correlation Analysis and Regression Analysis by using the Statistical Package for Social Science (SPSS) version 24.0. Findings indicate that In the same vein, results show that there is no significant difference in occupational stress among academic staff in public tertiary institutions in Lagos State, Nigeria based on gender [t (df = 641 ) = 1.888; ρ= 0.059> 0.05]. Also, the study found that there is no significant difference in occupational stress among academic staff in public tertiary educational institutions in Lagos State, Nigeria between Federal and State government institutions [t (df = 641 ) = -0.888; ρ= 0.375> 0.05]. It is concluded that occupational stress has a considerable influence on the lecturers’ productivity in tertiary educational institutions in Lagos State. The study therefore recommended that more academic staff should be employed. Tertiary educational institution managers, including vice-chancellors, Provosts, deans of faculties, and head of departments, should ensure that lecturers are assigned duties in line with their carrying capacities. Keywords: Stress, Occupational stress, Productivity, Academic staff, Public tertiary educational institution DOI: 10.7176/JEP/14-11-02 Publication date: April 30 th 2023