This study investigated managerial practices for the sustainability of quality in private secondary schools in Bayelsa State. The population was forty-five (45) government approved secondary schools in Bayelsa State. These were made up of five hundred and forty (540) respondents (495 teachers and 45 principals). A sample of 300 principals and teachers (25 principals and 275 teachers) were selected through stratified random sampling technique. Descriptive survey research design, five research questions and five hypotheses were used for the study. The instrument titled: Managerial Practices for Sustainability of Quality Questionnaire (MPSQQ) in the modified Likert scale rating of VGE, GE, LE, VLE validated with a reliability index of 0.65 was used to collect the needed data from the respondents. Out of 300 copies of questionnaires administered by the researcher, 264 copies were properly completed and used. The research questions were answered using mean and rank order while z-test statistics were used to test the stated hypotheses at the 0.05 level of significance. Findings showed that there were adherence to standards, provision of resources, employment of qualified teachers, etc.