thumb|Various Israeli officers of the Paratrooper Battalion 890 in 1955 with [[Moshe Dayan (standing, third from the left). Unit 101 merged with Paratrooper Battalion 890 upon disbandment. Meir Har-Zion is standing, first from the left and Ariel Sharon is standing, second from the left.]]
Commando Unit 101 () was a sayeret (commando) unit of the Israeli Defense Forces (IDF), founded and commanded by Ariel Sharon on orders from Prime Minister David Ben-Gurion in August 1953. They were armed with non-standard weapons and tasked with carrying out retribution operations across the state's borders—in particular, establishing small unit maneuvers, activation and insertion tactics.
Members of the unit were recruited only from agricultural kibbutzim and moshavim. Membership in the unit was by invitation only, and any new member had to be voted on by all existing members before they were accepted.
The unit was merged into the 890th Paratroop Battalion during January 1954, on orders of General Moshe Dayan, Chief of Staff, because he wanted their experience and spirit to be spread among all infantry units of IDF starting with the paratroopers. They are considered to have had a significant influence on the development of subsequent Israeli infantry-oriented units.
Background
Following the 1948 Arab–Israeli War, Israel was faced with cross-border raids and infiltrations by Arab militants and non-militants respectively. Many of these were small scale infiltrations that consisted of unarmed Palestinian refugees attempting to rejoin their families and of smugglers bringing in contraband for Israeli markets. These were later followed with attacks launched by refugees often motivated by economic reasons, but they were quickly adopted by the military of the neighboring Arab states, who organized them into semi-formal brigades which mounted larger scale operations from 1954 onwards. According to Israel, about 9,000 attacks were launched from 1949 to 1956, resulting in hundreds of Israeli civilian casualties.
At the same time the IDF was ill-prepared to respond to these raids. The Palmach, its three best combat units of the 1948 war, had been disbanded at Ben-Gurion's instruction. Many experienced officers had left the army after the war, and Israeli society had undergone a difficult period of impoverishment. As a result, the IDF did not have any units capable of effective reprisal, and did not perform well in offensive operations.