The study assessed the Impact of Leadership Styles of Principals on the Maintenance of Discipline and Facilities in Secondary Schools in Federal Capital Territory, Abuja. The study was carried out with six objectives among which are to: examine the impact of autocratic leadership styles of principals on maintenance of discipline and facilities in Secondary Schools in Federal Capital Territory, Abuja; ascertain the impact of democratic leadership styles of principals on maintenance of discipline and school facilities in secondary schools in the Federal Capital Territory, Abuja; and determine the impact of laissez-faire leadership styles of principals on maintenance of discipline and facilities in secondary schools in FCT, Abuja. Also, six corresponding research questions were raised and six null hypotheses formulated and tested in the study. Literatures were reviewed in the related areas of this study. Descriptive survey research design was used for the study. The population of this study comprised 56 principals, 3326 teachers and 55796 students in senior secondary schools in the Federal Capital Territory, Abuja. A sample size of 17 principals, 333 teachers and 382 students were used for the study. The sample size was arrived at using random sampling technique. A researcher-made instrument titled "Impact of Leadership Styles of Principals on the Maintenance of Discipline and Facilities" (ILSPMDF) was used to generate relevant data in this study. The instrument was validated by the researcher?s supervisors. A quantitative analysis of inquiry was performed using the Cronbach Alpha reliability coefficient technique and reliability value of 0.79 was obtained. Both descriptive and inferential statistics were used in the analysis of data. The descriptive statistics of frequencies and percentages, means and standard deviation were used to answer the research questions and the bio-data of respondents, while inferential statistics of Analysis of Variance (ANOVA) was used to test the postulated null hypotheses at an alpha of 0.05 level of significance. Findings revealed among others that in most secondary schools, principals who were autocratic gave orders and demand total obedience without explanations or questions when maintaining discipline. They maintained discipline alone without the interference of teachers and other staff. Also, in secondary schools where charismatic leadership was practiced, principals managed subordinate impressions by constantly demonstrating courage and conviction when maintaining discipline. The principals inspired subordinates in pursuit of a vision relating to discipline in their schools. Recommendations were made that principals should avoid being autocratic and promote only traits that cause followers to respect them and consider the leader as a working personnel and proud inspirational. In addition, principals should be aware of democratic leadership style and should apply its traits and strengths in practice. This will enhance more commitment and interest in maintaining discipline and facilities in schools. School principals should pay attention to transformational leadership factors quickly for effective maintenance of discipline and facilities in schools.