The Orebites (Czech: Orebité), also called Lesser Taborites and later known as Sirotci ("Orphans"; German: Waisen), officially Orphans' Union (Czech: Sirotčí svaz), were followers of a radical wing of the Hussites in Bohemia. The founders took part in the procession on Mount Oreb, near Třebechovice pod Orebem and Hradec. Founded in 1423 originally under the name Lesser Tábor, it consisted mostly of poorer burghers and some members of the Czech nobility who joined with the commander Jan Žižka.
The ideological founder of the Orebites was the priest Ambrož Hradecký. Leaders included Hynek Krušina of Lichtenburg and Diviš Bořek of Miletínek, the captain of the Hussites in Eastern and Central Bohemia. The Orebites were instrumental in the burning of the Benedictine monastery in Mnichovo Hradiště in the early summer of 1420, and in autumn, they supported the rest of the Hussites at the Battle of Vyšehrad.