The study examines one type of breaches of integrity, namely using one's authority in public office for personal gain (Hallak J & Poisson M. Corrupt schools, corrupt universities: what can be done? 2007), in the administration of teachers in Ghana. It was executed using an embedded mixed methods design with a population of 667 teachers employed by the Ghana Education Service (GES). A sample of 270 respondents was chosen by simple random sampling for the study. The questionnaire containing open-ended and closed-ended items was administered to the respondents. Data generated by the close-ended items were analysed using frequencies and percentages and data obtained from the open-ended items were analysed in themes. The study found that integrity breaches were prevalent in GES and occurred under the watch of superior officers in the service. It was more pronounced in teachers' requests for upgrading and promotion, and salary processing. Victims did not report the act because they believed nothing would happen and because they fear victimisation. Integrated Personnel and Payroll Database (IPPD) coordinators and Human Resource Managers at the district and regional levels of GES were found to be the most corrupt officers in the service. It is recommended that character references on GES staff be sought; the processing of salaries, transfer, upgrading, promotion, among others, at the GES offices should be automated; and effective whistleblower hotlines should be instituted.