Kitui County has about 40 Extra County Schools. Extra County Schools in Kenya are the previously called Provincial Schools; after National schools. St Charles Lwanga, St Monica, Mwingi Secondary, and Mutomo Girls are among the best performing Extra County Schools in Kitui County.
The schools admit students from all over the country. These schools are in 3 Categories i.e category 1 (C1), Category 2 (C2), and Category 3 (C3).
| SCHOOL CODE | SCHOOL NAME | CATEGORY | TYPE | CLUSTER |
| 13302102 | ST CHARLES LWANGA SCHOOL | Extra county | Boys | C1 |
| 13302103 | ST. ANGELA’S GIRLS SECONDARY SCHOOL | Extra county | Girls | C1 |
| 13302105 | ST THOMAS AQUINAS KALAWA BOYS | Extra county | Boys | C3 |
| 13302107 | ST URSULA GIRLS’ SECONDARY SCHOOL-TUNGUTU | Extra county | Girls | C2 |
| 13302108 | ST.MONICA GIRLS MULUTU SECONDARY SCHOOL | Extra county | Girls | C1 |
| 13310103 | YAMBYU GIRLS SECONDARY SCHOOL | Extra county | Girls | C2 |
| 13310102 | MWINGI SECONDARY SCHOOL | Extra county | Boys | C1 |
| 13317101 | MUTOMO GIRLS SECONDARY SCHOOL | Extra county | Girls | C1 |
| 13310201 | WAITA SECONDARY SCHOOL | Extra county | Mixed | C2 |
| 13339204 | THITANI SECONDARY SCHOOL | Extra county | Girls | C1 |
| 13328101 | KYUSO SECONDARY SCHOOL | Extra county | Boys | C1 |
| 13331201 | MUTONGUNI SECONDARY SCHOOL | Extra county | Boys | C1 |
| 13328102 | KIMANGAO GIRLS SECONDARY SCHOOL | Extra county | Girls | |
| 13331205 | KYONDONI GIRLS SECONDARY SCHOOL | Extra county | Girls | C1 |
| 13331204 | KATHEKA BOYS’ SECONDARY SCHOOL | Extra county | Boys | C2 |
| 13339101 | A I C KYOME BOYS SECONDARY SCHOOL | Extra county | Boys | C2 |
| 13339108 | MUSUANI SECONDARY SCHOOL | Extra county | Mixed | C2 |
| 13332102 | A.I.C SOMBE GIRLS SECONDARY SCHOOL | Extra county | Girls | C2 |
| 13339102 | MIGWANI SECONDARY SCHOOL | Extra county | Boys | C1 |
| 13339103 | A I C KYOME GIRLS SECONDARY SCHOOL | Extra county | Girls | C2 |
| 13338202 | ST. TERESA’S UKASI GIRLS’ SECONDARY SCHOOL | Extra county | Girls | C2 |
| 13365102 | ST. MARY’S MUTITO GIRLS SECONDARY SCHOOL | Extra county | Girls | C2 |
| 13366101 | GANKANGA SECONDARY SCHOOL | Extra county | Mixed | C2 |
| 13360101 | MATINYANI SECONDARY SCHOOL | Extra county | Boys | C1 |
| 13365101 | MUTITO BOYS SECONDARY SCHOOL | Extra county | Boys | C2 |
| 13357102 | IKUTHA GIRLS SECONDARY SCHOOL | Extra county | Girls | C2 |
| 13351102 | CHULUNI GIRLS’ SECONDARY SCHOOL | Extra county | Girls | C1 |
| 13339201 | NGUUTANI SECONDARY SCHOOL | Extra county | Boys | C2 |
| 13339105 | NZAUNI SECONDARY SCHOOL | Extra county | Mixed | C2 |
| 13339106 | ITOLONI GIRLS SECONDARY SCHOOL | Extra county | Girls | C2 |
| 13339107 | KYAMBOO SECONDARY SCHOOL | Extra county | Mixed | C1 |
| 13339301 | NZELUNI GIRLS SECONDARY SCHOOL | Extra county | Girls | C2 |
| 13344101 | ST LUKES YATTA SECONDARY SCHOOL | Extra county | Boys | C1 |
| 13351101 | ST.PETER’S NZAMBANI BOYS SECONDARY SCHOOL | Extra county | Boys | C3 |
| 13353102 | ITOLEKA SECONDARY SCHOOL | Extra county | Girls | C3 |
| 13354101 | KISASI SECONDARY SCHOOL | Extra county | Boys | C1 |
| 13354201 | MBITINI GIRLS’ SECONDARY SCHOOL | Extra county | Girls | C1 |
| 13357101 | IKUTHA BOYS SECONDARY SCHOOL | Extra county | Girls | C1 |
| 13353301 | MALIKU GIRLS’ SECONDARY SCHOOL | Extra county | Girls | C1 |
| 13353201 | MULANGO GIRLS HIGH SCHOOL | Extra county | Girls | C1 |