This study on the Assessment of the Contributions of Non-Governmental Organisations to the Development of Secondary Education in North-Central Geographical Zone, Nigeria was aimed at gathering information on the opinions of principals, teachers, Ministry of Education officials and Non-Governmental Organizations officials on the contributions of Non-Governmental Organizations in the development of secondary education. The study had seven objectives, which aimed to ascertain; teachers‟ capacity building, the provision of teaching facilities, the provision of learning facilities among others by Non-Governmental Organizations on the development of secondary education in North-Central Geographical Zone, Nigeria. Seven research questions were asked while corresponding hypotheses were formulated. Descriptive survey design was used for the study. A total of 384 population comprising 82 principals, 172 teachers, 95 MOE officials and 35 NGO officials were used. Respondents were randomly drawn from the population using simple random sampling procedure. The instrument used for data collection was self-developed questionnaire using modified five points Likert scale of measurement. The questionnaire was validated by the researcher‟s supervisory team and experts in research and statistics in the department. The instrument was found to be reliable through pilot study which was carried out in Federal Capital Territory. All the seven hypotheses formulated were tested using One Way Analysis of Variance (ANOVA) at 0.05 level of significance. The major findings of this research indicated that Non-Governmental Organizations played key role in staff capacity building through organizing and sponsoring various staff development programmes such as workshop, conferences, seminar; Non- Governmental Organization assisted in the provision of teaching facilities but do not provide flip chart, ICT facilities and textbook; Non-Governmental Organizations did not provide learning facilities except exercise books, pencils, erasers, mathematical set to Secondary Schools; Non-Governmental Organizations didn‟t under take Supervision of Instruction in Secondary Schools among others. Conclusions included that Staff capacity building by Non-Governmental Organizations like workshop, conferences and seminars for teachers, immensely in the development of secondary education in North-Central Geographical Zone, Nigeria because it is an effective method of increasing the knowledge and skills of teachers in order to teach more effectively, provision of facilities for Teaching by Non-Governmental Organizations such as flip charts and models for teaching, laboratories and workshops, computers and ICT facilities has immense contribution to the development of secondary education in North-Central Geographical Zone, Nigeria because available adequate and teaching facilities promote academic achievements, provision of adequate facilities for Learning by Non-Governmental Organizations such as classrooms, relevant text books has great contributions to the development of secondary education in North-Central Geographical Zone, Nigeria because adequate and relevant facilities promote academic achievements, instructional Supervision has great contributions to the development of secondary education in North-Central Geographical Zone, Nigeria because it aims at improving practice, improving student learning achievement, reflection, and improving the overall school among others. Recommendations were made which include Non-Governmental Organizations should endeavor to increase their areas of coverage in terms of provision of capacity building programmes for teachers to benefit more, Non-Governmental Organizations should extend the provision of teaching facilities to schools in the rural areas so for the benefits to go round among others.