This study investigated communication flow and participation in decision making as determinants of job performance among academic staff in tertiary institutions in Ekiti State. Two hypotheses were formulated to guide the study. Sample of 450 respondents were selected using simple random and Proportionate sampling techniques. A structured questionnaire was used in data collection from the respondents. In other to ascertain the validity of the instrument used was given to experts in faculty of Education, Ekiti State University for both face and content validity. The reliability of the instrument was carried out using test re-test method and reliability coefficient obtained was 0.75. The findings of the study revealed that there was significant relationship between communication flow and job performance of academic staff in tertiary institutions in Ekiti State. The study also revealed that there was significant relationship between participation in decision making and job performance of academic staff in tertiary institutions in Ekiti State. Based on the findings, it was recommended that the Management of tertiary institutions should involve the academic staff in the decision making concerning the institutions for improved job performance and there should be a good communication link between the management and the academic staff in order to facilitate strong and mutual understanding towards enhancing effective administration of the system.