K
- König
- Kalep
- Kawasaki Heavy Industries Aerospace Company — Japan
- Kawasaki Heavy Industries
- Keikaufer
- Kemp
- Ken Royce — Kansas City, Missouri, U.S.
- Kessler
- KHD
- Kimball
- King-Bugatti
- Kinner — U.S.
- Kirkham
- Klimov — Russia/Soviet Union
- Klöckner-Humboldt-Deutz — Germany
- Knox
- Koerting
- Kolesov
- Konrad
- Korting
- Kostovich
- Kroeber
- Kuznetsov — Russia/Soviet Union
Read more about this topic: List Of Aircraft Engine Manufacturers