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 Marsabit County:
| NAME | KNEC CODE | TYPE | CATEGORY | |
| 1 | SAKUU HIGH SCHOOL | 16305302 | Boys | County |
| 2 | MAIKONA GIRLS SECONDARY SCHOOL | 16320301 | Girls | County |
| 3 | HON. ISACKO MEMORIAL BOYS HIGH SCHOOL | 16320401 | Boys | County |
| 4 | LAISAMIS SECONDARY SCHOOL | 16321101 | Boys | County |
| 5 | LOGLOGO GIRLS SECONDARY SCHOOL | 16321102 | Girls | County |
| 6 | NORTH HORR SECONDARY SCHOOL | 16358101 | Boys | County |
| 7 | NORTH HORR GIRLS SECONDARY SCHOOL | 16358102 | Girls | County |
| 8 | KULAL GIRLS SECONDARY SCHOOL | 16359102 | Girls | County |