This study investigated the relationship between Big Five personality trails and teachers vocational adjustment in modern Nigeria educational system, using Rivers state as a case study. The study was conducted in all the public primary schools and secondary schools in Rivers state, restricted only to the 13000 teachers employed in 2013 by Rivers state government. Two research questions and two corresponding null hypotheses guided the study. Ex-post Facto research design was adopted and a sample size of 210 was purposively selected for the purpose of the study. Two instruments named: Big Five Inventory (13F1) and Vocational Adjustment Test (VAT) were employed for data collection. The reliability of the instruments were ascertained. Multiple regression, Person Product Moment Correlation Statistic, ANOVA and t-test associated with multiple regression were used to analysis the data collected. Results got after data analysis indicated that the joint Five personality traits: openness to experience, conscientiousness’, extraversion. agreeableness and neuroticism significantly relates with teachers vocational adjustment. But when analyzed indepen1ently, neuroticism and extroversion did not have significant relationship with teachers’ vocational adjustment. Based on these findings, appropriate recommendations were made among  which was that Education stakeholders should employ the use of personality aptitude test before appointing teaching staff, in order to ensure that teachers are really possessing personality attributes suited for the teaching profession and vocational aptitude test should be a must for job placement in Nigeria.