Science magazines
- Jones Cycladenia
- June Sucker
- Ka'u Silversword
- Kamakahala (Labordia cyrtandrae)
- Kamakahala (Labordia lydgatei)
- Kamakahala (Labordia tinifolia var. lanaiensis)
- Kamakahala (Labordia tinifolia var. wahiawaensis)
- Kamakahala (Labordia triflora)
- Kanab Ambersnail
- Karner Blue Butterfly
- Kaua'i Nukupu'u
- Kauai 'Akialoa
- Kauai 'O'o
- Kauai Cave Amphipod
- Kauai Cave Wolf Spider
- Kauai Hau Kuahiwi
- Kauila
- Kaulu
- Kearney's Blue-star
- Keck's Checker-mallow