Background: The Teacher Stress Inventory (TSI) is an instrument used for assessing occupational stress among teachers but has not been adapted or validated for use in Nigeria.Objective: This study aimed to modify and adapt the TSI for use in Nigeria and also assess its reliability and validity. An expert panel was constituted to modify the original version of the TSI. Thereafter, both the original and the modified versions were applied to 471 teachers from 15 schools in Oyo State, Nigeria.