County secondary schools in Kenya form the third tier after national and extra-county schools respectively.
Most of Kenyan learners are absorbed by these schools.
Admission to county schools is done online by the Ministry of Education.
They are either mixed or single-sex.
Here is a list of county secondary schools in Busia County:
| KNEC CODE | NAME OF THE SCHOOL | TYPE | CATEGORY | |
| 1 | 35601101 | ST. MATHIAS’ BUSIA SECONDARY SCHOOL | Boys | County |
| 2 | 35601102 | OUR LADY OF MERCY | Girls | County |
| 3 | 35606104 | MODING HIGH SCHOOL | Mixed | County |
| 4 | 35606106 | KATAKWA SECONDARY SCHOOL | Mixed | County |
| 5 | 35606107 | S A ABOLOI SECONDARY SCHOOL | Mixed | County |
| 6 | 35606108 | ALBERT EKIRAPA SECONDARY SCHOOL | Mixed | County |
| 7 | 35606116 | ST MARTIN’S MWARI SECONDARY SCHOOL | Mixed | County |
| 8 | 35606202 | ST JOSEPHS KOCHOLIA SECONDARY SCHOOL | Mixed | County |
| 9 | 35606203 | ST.THOMAS AMAGORO GIRLS SECONDARY SCHOOL | Girls | County |
| 10 | 35606204 | ST. AUGUSTINE KAMOLO SECONDARY SCHOOL | Mixed | County |
| 11 | 35610102 | JOHN OSOGO SECONDARY SCHOOL | Boys | County |
| 12 | 35610103 | ST.CECILIA NAMENYA GIRLS SCHOOL | Girls | County |
| 13 | 35610106 | ST ANNE’S BUNYALA GIRLS SECONDARY SCHOOL | Girls | County |
| 14 | 35620102 | ST. MARY’S AMUKURA GIRLS HIGH | Girls | County |
| 15 | 35623101 | BUHUYI SECONDARY SCHOOL | Mixed | County |
| 16 | 35623103 | ST. CLARE BUTULA GIRLS’ SECONDARY SCHOOL | Girls | County |
| 17 | 35623104 | LUGULU A.C SECONDARY SCHOOL | Boys | County |
| 18 | 35623106 | BUKHALALIRE SECONDARY SCHOOL | Boys | County |
| 19 | 35623107 | ST. JOSEPH’S BUMUTIRU SECONDARY SCHOOL | Mixed | County |
| 20 | 35623108 | BUJUMBA BOYS’ SECONDARY SCHOOL | Boys | County |
| 21 | 35623124 | BUJUMBA GIRLS’ SECONDARY SCHOOL | Girls | County |
| 22 | 35629104 | ST THOMAS AQUINAS MADENDE SECONDARY SCHOOL | Mixed | County |
| 23 | 35629106 | MALANGA MIXED SECONDARY SCHOOL | Mixed | County |
