The Sukhoi Su-33 (Russian: Сухой Су-33) is an all-weather carrier-based air defence fighter designed by Sukhoi and manufactured by KnAAPO. It is a derivative of the Sukhoi Su-27 and was initially known as the Su-27K. First used in operations in 1995 aboard the carrier Tbilisi and Riga, the fighter officially entered service in August 1998, by which time the designation "Su-33" was used. Compared with the Su-27, the Su-33 has a strengthened undercarriage and structure, folding wings and stabilators, all for carrier operations. The wings are larger than on land-based aircraft for increased lift. The Su-33 has upgraded engines and a twin nose wheel, and is air refuellable.
- Sukhoi Su-27K: Carrier-based version of the Su-27 designed for operations from the Project 11435, Project 11437, and Project 1160 aircraft carriers (heavy aircraft cruiser in Soviet designation).
- Sukhoi Su-27KI: Carrier-based version of the Su-27 designed for operations from the Project 1153 aircraft carriers (heavy aircraft cruiser in Soviet designation).
- Sukhoi Su-27KPP: Two-seat carrier-based electronic-warfare aircraft.
- Sukhoi Su-27KRTS: Two-seat carrier-based reconnaissance and target designation aircraft.
- Sukhoi Su-27KT/KTZ: Carrier-based tanker aircraft.
- Sukhoi Su-27KU: Two-seat carrier-based trainer.
- Sukhoi Su-27KSH: Carrier-based attack aircraft based on the Su-27.
- Sukhoi Su-29K: Carrier-based interceptor aircraft based on the Su-27 with a possibility to carry the long-range R-33 air-to-air missiles.
- Sukhoi Su-33: Designation for the Su-27K after its introduction into service with the Soviet Naval Aviation.
- Sukhoi Su-33KUB/UB: Two-seat training-and-combat version based on the Su-27K and Su-27KU with side-by-side seating for crew of two. One prototype built.
- Sukhoi Su-33M: Extensive upgrade of the Su-33 with more powerful engines and modern avionics, electronics and weapons.