Kiambu County has twelve constituencies. Together with Kakamega County, they have the second largest number of constituencies after Nairobi. See the list below:
- Gatundu South
- Gatundu North
- Juja
- Thika Town
- Ruiru
- Githunguri
- Kiambu
- Kiambaa
- Kabete
- Kikuyu
- Limuru
- Lari