The objective of the study was to determine extent principals involve teachers in decision-making for effective secondary school administration. Two research questions were answered and two hypotheses were tested at 0.05 level of significant. It was a descriptive survey. The area of study was Anambra State. A total of 6,654 respondents made up of 258 principals in public secondary schools and 6,396 principals in private secondary schools in Anambra State formed the population for the study. The sample for this study consisted of 774 respondents made up of 129 principals, and 645 teachers. Multi-stage sampling procedure was used to draw774 respondents made up of 129 principals and 645 teachers.A questionnaire titled ‘Principals’ Involvement of Teachers in Decision Making Questionnaire (PITDMQ)’ developed by the researchers was used for data collection. The instrument was validated by three experts. Cronbach alpha was used for test of internal consistency of PITDMQ and the reliability indices obtained for the two clusters were 0.80 and 0.76 respectively. The researchers together with five research assistants collected data for the study using direct administration method and 98% return rate was recorded. Mean scores and standard deviation were used to answer the research questions while t-test was used to test the hypotheses. The findings of the study revealed among others that principals’ involvement of teachers in decision making on students’ and staff affairs to a great extent. It was also reported that there is no significant difference in the mean ratings of principals and teachers on the extent of principals involvement of teachers in decision making on students affairs issues. Based on the findings, it was recommended among others that Ministry of Education should organize regular interactive sessions for principals and teachers to exchange ideas and gain information to improve their collaborative decision makings on students’ affairs.

Keywords : Principals’ Involvement; Decision-Making; Effective Administration; Secondary School; Students’ Affairs; Staff Affairs.