- CMS Grammar School, Bariga, Lagos (1859) – CMS
- Methodist Boys High School, Victoria Island, Lagos (1878) – Methodist
- Methodist Girls High School, Yaba, Lagos (1879) – Methodist
- Baptist Academy, Obanikoro, Lagos (1885) – Baptist – The primary school arm was established in 1855 but was not changed into secondary school
- Hope Waddell Training Institute, Calabar (1895) – United Presbyterian
- St. Anne’s School, (Old Kudeti Girls’ School) Ibadan (1896)*- CMS
- Oron Boy’s High School, (Old Oron Training Institute) Oron (1897)*- CMS
- Wesley College of Science (old Wesley College), Elekuro, Ibadan (1905)* – Methodist
- St. Paul’s College, Iyenu, Awka (1900)* – CMS
- Methodist Boy’s High School, Oron (1905) – Methodist
- Abeokuta Grammar School, Idi-Aba, Abeokuta (1908) – CMS
- King’s College, Catholic Mission street, Lagos (1909) – Government
- St. John’s School, Bida (1909)* – CMS
- Alhuda-Huda College(Old Government Secondary School), Zaria (1910) – Government
- Ijebu-Ode Grammar School, Ijebu-Ode (12 Jan. 1913) – Anglican
- Eko Boys High School, Mushin, Lagos (13 Jan. 1913) – Methodist
- Ibadan Grammar School, Molete, Ibadan (Mar. 1913) – CMS
- Government Secondary School, Ilorin, Kwara (1914)- Government
- Government College, Katsina-Ala, Benue (1915) – Government
- Etinan Institute, Etinan, Akwa-Ibom (1915) – Qua Iboe Christian Mission
- Ondo Boys High School, Ondo (1919) – CMS
- Duke Town Secondary School (1919) – Qua Iboe Christian Mission
- Baptist Boys High School, Oke-Saje, Abeokuta (1923) – Baptist
- Government College, Kaduna (1920) – Government
- Barewa College, (Old Katsina College, Kaduna College and Government College), Zaria (Established as Katsina Teachers’ College) (1921)* – Government
- Methodist College, Uzuakoli, Abia (1923)- Methodist
- Ibo Boys’ High School, Uzuakoli, Abia (1923) – CMS
- Dennis Memorial Grammar School, Onitsha, Anambra (1925) – CMS
- Queens College, Yaba, lagos (1927) – Government
- Government College, Apata, Ibadan (1927) – Government
- Government College, Umuahia, Abia (1927) – Government
- United Memorial Grammar School, Ibadan (1928) – CMS
- St. Gregory College, Ikoyi, Lagos (1928) – Catholic
- St. Thomas College, Ibusa (1928) – CMS
- St. Charles College, Onitsha (1929) – CMS
- Aggrey Memorial College, Arochukwu (1931) – Individual (Alvan Ikoku)
- Igbobi College, Yaba, Lagos (1932) – Methodist/CMS
- St’ Theresa College, Oke-Ado, Ibadan (1932) – Catholic
- Oduduwa Grammar School, Ile-Ife (1932) – CMS
- Christ the King College, Onitsha, Anambra (1933) – Catholic
- Christ’s School, Fajuyi Park, Ado-Ekiti, Ekiti (1933) – CMS
- Ilesha Grammar School, Ilesha, Osun (1934) – Social Group (Egbe Atunlese Ijesha)
- St. Patrick’s College, Calabar (1934) – Catholic
- Holy Rosary College, Enugu (1935) – Catholic
- Government Secondary School, Owerri (1935) – Government
- Edo College, Benin City (1937) – Government
- Ibadan Boys High School, Ibadan (1938) – Individual (Chief T.L. Oyesina)
- Baptist High School, Bodija, Ibadan (1940) – Baptist
- Queen of the Rosary College, Onitsha (1942) – Catholic
- African Church School, Kajola, Ifo (1943)*
- Lisabi Grammar School, Abeokuta (1943)
- Offa Grammar School, Offa (1943)
- Olivet Heights, Oyo (1945)
- Adeola Odutola College (old Olu-Iwa College), Ijebu-Ode (1945)
- Government College, Ughelli (1945)
- Anglican Girls’ Grammar School, Lagos (1945)
- Urhobo College, Effurun (1946)
- Remo Secondary School, Sagamu (1946)
- Ansar –Ud – Deen Comprehensive College, Otta (1946)
- Imade College, Owoh (1946)
- Victory College, Ikare, Ondo (1947)
- Hussey College, Warri (1947)
- Ahmaddiya (Anwar-ul-Islam) College, Agege, Lagos (1948)
- Government College, Keffi (old Keffi Secondary School situated in Kaduna) (1949)
- Molusi College, Ijebu-Igbo (1949)
- Baptist High School, Borokiri, Port Harcourt (1949)
- Oriwu College, Ikorodu (1949)
- Ago-Iwoye Secondary School, Ago-Iwoye (1950)
- Ijebu Muslim College (1950)
- Our Ladies of Apostle Secondary School, Yaba, Lagos (1950)
- St. Peter Claver’s College, Sapele (1950)
- Egbado (Yewa) College, Ilaro (1950)
- St. Thomas’s Aquinas College, Akure (1951)
- Queen’s School, Ibadan (1952)
- Government College, Afikpo, Ebonyi (1952)
- Oyemekun Grammar School, Akure (1953)
- Loyola College, Ibadan (1954)
- St. Bernadine’s, Oyo (1954)
- Our Ladies of Apostle Secondary School, Ijebu-Ode (1954)
- St. Anthony’s Grammar School, Ijebu-Imushin (1954)
- Manuwa Memorial Grammar School, Iju-Odo ( 1954)
- Fiditi Grammar School, Fiditi, Oyo (1954)
- National High School, Arondizuogu, Imo (1954)
- Iheme Memorial Grammar School, Arondizuogu, Imo (1954)
- St. Louis Secondary School, Ondo (1954)
- Gboluji Grammar School, Ile-Oluji, Ondo (1954)
- Badagry Grammar School, Badagry (1955)
- African Church Grammar School, Abeokuta (1955)
- Ibara Anglican High School, Abeokuta (1955)
- Doherty Memorial Grammar School, Ijero- Ekiti (1955)
- St Patrick’s College, Asaba (1955)
- St. Monica Girls’ School, Ondo (1955)
- St. Catherine’s Anglican Girls School, Owo (1956)
- St Joseph’s College, Ondo (1956)
- Methodist High School, Okiti Pupa (1956)
- Mayflower School, Ikenne (1956)
- Isoyin Grammar School, Isoyin (1956)
- Ebenezer Grammar School, Abeokuta (1956)
- St. Joseph College, Ondo (1956)
- Odogbolu Grammar School, Odogbolu (1957)
- Notre Dame College, Ozoro (1957)
- Government College, Makurdi (1957)
- Holy Rosary College, Idah (1957)
- Anglican Grammar School, Iju-itaogbolu (1957)
- African Church Grammar School, Oka-Akoko (1957)
- Okemesi Grammar School, Okemesi-Ekiti (1958)
- Lagelu Grammar School, Ibadan (1958)
- Ahmadu Bahago Secondary School (old Niger Baptist College), Niger (1958)
- Anglican Grammar School, Igbara-Oke (1958)
- St. Patrick’s College, Oka-Akoko (1959)
- Ondo Anglican Grammar School, Ondo (1959)
- Premier Grammar School, Abeokuta (1959).
Is yours there? MINE IS 35 , WHICH ONE IS YOURS?