A tankette is a tracked armoured fighting vehicle resembling a small tank roughly the size of a car, mainly intended for light infantry support or scouting. Colloquially it may also simply mean a "small tank".
Tankettes were designed and built by several states between the 1920s and 1940s, and saw some combat (with limited success) in World War II. However, the vulnerability of their light armor eventually caused the concept to be abandoned.
Tankettes were made both in one- or two-man models. Some were so low that the occupant had to lie prone. Some models were not equipped with turrets (and together with the tracked mobility, this is often seen as defining for the concept), or just a very simple one that was traversed by hand or leg. They are significantly smaller than light tanks and do not have a tank gun, instead their main weapon tended to be one or two machine guns, or rarely a 20mm gun or grenade launcher.
The genesis of the tankette concept was the armoured warfare of World War I. On the Western Front in the later stage of the war, Allied tanks could break through the enemy trench lines but the infantry (needed to take and hold the ground gained) following the tanks were easily stopped or delayed by small arms fire and artillery. The breakthrough tanks were then isolated and destroyed and reinforcement plugged the hole in the trench line. The tankette was originally conceived in the early interwar period to solve this problem. The first designs were a sort of mobile, one man machine gun nest protected against small arms fire and shell fragments. This idea was abandoned and the two man model, mainly intended for reconnaissance, was produced instead. The moving up of infantry while protecting them was solved with the armoured personnel carrier.
In 1925 British tank pioneer Giffard Le Quesne Martel built a one-man tank - the Morris-Martel - in his garage and showed it to the War Office who agreed production of a few for testing. The publicity caused John Carden and Vivian Loyd to produce their own. Both types were developed further but the two-man Carden Loyd tankette was considered the classic and most successful design, with many other tankettes modelled after it. While the design was influential, few Carden Loyd tankettes saw combat, some of them on the Bolivian side during the Chaco War. However, the design did lead to more capable vehicles in the Universal Carrier which had as its origins in Carden Loyd tankette and that had an extensive operational history in the Second World War 
The Italian Royal Army (Regio Esercito) equipped three armoured divisions and three "fast" (celere) divisions with L3/33 and L3/35 tankettes. L3s were used in large numbers during the Italian invasion of Ethiopia, the Spanish Civil War, and almost every place Italian soldiers fought during World War II. L3s even went with the Italian Expeditionary Corps in Russia (Corpo di Spedizione Italiano, or CSIR) as late as Operation Barbarossa.
The French Armoured Reconnaissance type of the 1930s (Automitrailleuses de Reconnaissance, "machine-gun scout") was essentially a tankette in form, but specifically intended for scouting ahead of the main force.
The Imperial Japanese Army became one of the most prolific users of tankettes, producing a number of designs useful for jungle warfare. However, by the time of the Second World War, many were already obsolete or were found to be unsuccessful in their appointed task. Many ended up being relegated to tractor duties for artillery or logistics units.
The concept was later abandoned due to limited usefulness and vulnerability to anti-tank weapons and even machine guns, and the role of the tankette was largely taken over by armoured cars. However, in the Vietnam War the US Army employed the similar, somewhat larger, M50 Ontos, with respectable success.
The 1990s saw the renaissance of a similar concept with the Wiesel of the German Bundeswehr being introduced to provide airborne troops with armoured reconnaissance capability, a function that had already been tried with Soviet T-27 in World War II. However, the WWII-contemporary term "tankette" is not used for these modern vehicles (they are termed "armoured weapons carriers" in the Bundeswehr), although they do fit the definition of a tankette.
- British: Carden Loyd
- Italian: L3/33 and L3/35
- Japanese: Type 92 Jyu-Sokosha, Type 94 tankette, and Type 97 Te-Ke (with rotating turret)
- Polish: TKS/TK-3
- Czechoslovak: AH-IV, Tančík vz. 33
- Soviet: T-27
- France: Renault UE Chenillette
- German: Wiesel 1 and Wiesel 2 (similar modern German armored and tracked weapon carrier systems)
- The Revolution After Next: Making Vertical Envelopment by Operationally Significant Mobile Protected Forces a Reality in the First Decade of the 21st Century, Tedesco, Vincent J. III; Major, School of Advanced Military Studies , United States Army Command and General Staff College, Fort Leavenworth, United States, 2000, Page 15
- Iron Arm (book excerpt via Google Books), Sweet, John Joseph Timothy; Stackpole Books, 2007, Page 84)
- T-27 Tankette (from the 'battlefield.ru' website, with further references cited. Accessed 2008-02-21.)
- War Slang: American Fighting Words and Phrases Since the Civil War (book excerpt via Google Books), Dickson, Paul; Brassey's, 2004, Page 221)
- Fletcher & Bryan, p. 3
- U.S. Forces Encounter Old Jap Tankette (from Intelligence Bulletin, September 1945, via lonesentry.com. Retrieved 2008-01-06.)
- Wiesel 1 (product website from the Rheinmetall manufacturer website. Accessed 2008-05-29.)