This study assessed principals' leadership styles on the management of Federal Unity Colleges in North-Central Geo-Political Zone, Nigeria. Seven research questions were formulated and seven null hypotheses were stated and tested to answer the research questions. The research design adopted was descriptive survey carried out ex post facto. The study population schools comprised all the 24 Unity Schools in the Zone. Out of this population, a sample of 12 Unity Schools was taken and selected through the systematic sampling technique. Out of the 2,345 staff (including principals) in the sampled schools, a sample size of 245staff was selected using stratified proportional random sampling techniques. The sample size was made up of 36 management staff (including principals), 132 academic staff and 77 non-academic staff.For the data collection, only the primary data collection technique was used by the researcher. Questionnaire was given to sample schools in order to get needed data. The seven null hypotheses were tested using one-way Analysis of Variance (ANOVA) to determine the difference in the opinions of the management staff, academic staff and non-academic staff. From the findings of this study, three hypotheses were retained while four were refused to be retained. It was, however, discovered that principals in the study area commonly adopted autocratic and nomothetic leadership styles in performing their leadership role in the Colleges against democratic, idiographic and transformational leadership styles. On this basis, the researcher recommended that autocratic style, nomothetic style and laissez- faire style are not suitable in the school environment rather democratic style, idiographic style and transformational style should be encouraged. Finally, the Federal Ministry of Education should rescued the various colleges in the study area by providing training and re-training, give room to further studies, organise refresher courses,workshop and seminars for principals on effective leadership styles in the school system so as to strengthen their professional competences and enhance their efficiency in the management of their schools.