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 Schools in Nyeri County:
| NAME | KNEC CODE | TYPE | CATEGORY | |
| 1 | MUTHUAINI SECONDARY SCHOOL | 08202008 | Girls | County |
| 2 | GACHIKA SECONDARY SCHOOL | 08202011 | Mixed | County |
| 3 | ST. MONICA MUNYAKA GIRLS SECONDARY SCHOOL | 08210202 | Girls | County |
| 4 | NDATHI SECONDARY SCHOOL | 08210301 | Boys | County |
| 5 | GATONDO SECONDARY SCHOOL | 08217102 | Girls | County |
| 6 | KIARITHA-INI HIGH SCHOOL | 08217103 | Boys | County |
| 7 | GIAKAIBII SECONDARY SCHOOL | 08217104 | Boys | County |
| 8 | KARATINA SECONDARY SCHOOL | 08217201 | Girls | County |
| 9 | MAGUTU GIRLS’ SECONDARY SCHOOL | 08217204 | Girls | County |
| 10 | MATHAITHI SECONDARY SCHOOL | 08217205 | Girls | County |
| 11 | ICUGA SECONDARY SCHOOL | 08218104 | Girls | County |
| 12 | RUTHAGATI HIGH SCHOOL | 08218201 | Boys | County |
| 13 | KABIRUINI SECONDARY SCHOOL | 08218203 | Girls | County |
| 14 | HIRIGA SECONDARY SCHOOL | 08218204 | Girls | County |
| 15 | KIAMARIGA SECONDARY SCHOOL | 08218207 | Boys | County |
| 16 | TAMBAYA SECONDARY SCHOOL | 08219104 | Mixed | County |
| 17 | ST.AUGUSTINE GIKONDI BOYS SECONDARY SCHOOL | 08219105 | Boys | County |
| 18 | GATHUNGURURU GIRLS SECONDARY SCHOOL | 08219106 | Girls | County |
| 19 | MWERU HIGH SCHOOL | 08219107 | Mixed | County |
| 20 | NDIAINI GIRLS’ HIGH SCHOOL | 08219108 | Girls | County |
| 21 | ST ANNE GITHUNGURI GIRLS | 08219109 | Girls | County |
| 22 | KARUNDU MIXED SECONDARY SCHOOL | 08219126 | Mixed | County |
| 23 | MWIYOGO SECONDARY SCHOOL | 08220104 | Mixed | County |
| 24 | WATUKA SECONDARY SCHOOL | 08220202 | Boys | County |
| 25 | MUGUNDA SECONDARY SCHOOL | 08220401 | Girls | County |
| 26 | DR. KAMUNDIA GATHUTHI GIRLS SECONDARY SCHOOL | 08221103 | Girls | County |
| 27 | WAMAGANA GIRLS SECONDARY SCHOOL | 08221107 | Girls | County |
| 28 | GATHATHI-INI SECONDARY SCHOOL | 08221205 | Girls | County |
| 29 | HUHO-INI GIRLS HIGH SCHOOL | 08221206 | Girls | County |
| 30 | AGUTHI SECONDARY SCHOOL | 08221302 | Mixed | County |
| 31 | GATUGI GIRLS SECONDARY SCHOOL | 08237011 | Girls | County |
| 32 | IRIA-INI GIRLS’ HIGH SCHOOL | 08237016 | Girls | County |
| 33 | KIHOME SECONDARY SCHOOL | 08237017 | Mixed | County |
| 34 | MUCHARAGE SECONDARY SCHOOL | 08237018 | Girls | County |
| 35 | KAGONYE SECONDARY SCHOOL | 08237020 | Mixed | County |
