The Right Sector Ukrainian Volunteer Corps (Ukrainian: Добровольчий український корпус «Пра́вий се́ктор», ДУК ПС, romanized: Dobrovolʹchyi ukrainsʹkyi korpus "Právyi séktor", DUK PS) or simply the Ukrainian Volunteer Corps (Ukrainian: Добровольчий український корпус, ДУК, romanized: Dobrovolʹchyi ukrainsʹkyi korpus, DUK), was the paramilitary arm of right-wing Ukrainian nationalist party Right Sector. The Ukrainian Volunteer Corps was founded on July 17, 2014, as one of the "volunteer battalions", created as a response to the rise of pro-Russian separatism and the 2014 Russian invasion which started the War in Donbas.

They officially defined themselves as a "voluntary formation of Ukrainian citizens, Ukrainians from abroad and non-Ukrainians - citizens of other countries who share the ideology of Ukrainian nationalism and have expressed a desire to participate in the Ukrainian people's armed struggle against external and internal enemies." The Ukrainian Volunteer Corps was mostly made up of members of Right Sector, but also accepts volunteers without any party affiliations, as well as foreigners. The DUK was founded by Dmytro Yarosh—nom-de-guerre "Yastrub" ("Hawk")—who was also the leader of Right Sector, from an irregular militia that the Right Sector formed during the Euromaidan, which patrolled the streets after the fall of the Yanukovych government. In 2015, after Yarosh's resignation, he announced the creation of the Ukrainian Volunteer Army, a new paramilitary unit made up of former units of the DUK, another split also resulted in the creation of the separate Santa Unit by Volodymyr Regesh.

In July 2014, the DUK claimed to have 5,000 troops. The group was involved in combat during the war in Donbas and later in the 2022 Russian invasion of Ukraine. Most of the Ukrainian volunteer battalions were later integrated by the Ukrainian government into either the Ukrainian Ground Forces or the Ukrainian National Guard, but the DUK was one of the few that remained autonomous. This changed with the 2022 invasion, when they were formally absorbed in the Ground Forces as a special operations unit. In November 2022, the Ukrainian Volunteer Corps was reformed as the 67th Separate Mechanized Brigade "DUK", and were training in the United Kingdom. In April 2024, the 67th Brigade was disbanded and its members transferred to other brigades of the Ground Forces due alleged preferential treatment of Right Sector members, which led to repeated losses in Chasiv Yar, and failures to reform the old volunteer battalion structure into an official military structure.

The Ukrainian Volunteer Corps has its origins in vigilante militias created by the Right Sector formed during the Euromaidan and the Revolution of Dignity. After the fall of the Yanukovych government, the police largely abandoned the streets of Kyiv and groups of young men, including members of Right Sector, patrolled them armed mostly with baseball bats and sometimes with guns. The guns the Right Sector volunteers had were stolen from the Militsiya at the end of the Maidan.

In 12 April, the pro-Russian unrest escalated when armed pro-Russian militants seized control city of Sloviansk. The Ukrainian government responded with an offensive against the separatists, marking the first major military engagement of the war in Donbas (2014–2022). On 20 April, Yarosh led a group of armed Right Sector members who were covertly sent by acting Ukrainian President Oleksandr Turchynov to destroy the transformer of the Sloviansk television station on Karachun mountain. When their four-car convoy attempted to pass an insurgent-controlled checkpoint, a gunfight broke out, leading to the first combat fatalities of the conflict. The Ukrainian government denied that the attack was carried out by Right Sector until two years later, when Yarosh admitted that it was true. There is still dispute over which side shot first.

After the eruption of the war in Donbas in April 2014. The regular Ukrainian Armed Forces suffered a number of defeats and setbacks against the separatists, as they were ill-prepared, ill-equipped, lacking in professionalism, morale, and fighting spirit, and with severe incompetence in the high command. The reaction to these failures saw the creation of various "volunteer battalions" militias and paramilitary groups formed by willing civilians to fight the separatists on their own initiative. Many volunteers of the Right Sector initially formed the "Dnipro-2" volunteer battalion—in reference to Dnipro-1—however, the Ministry of Internal Affairs refused to register that as the name of group.

On July 15 2014, Yarosh announced the creation of the Ukrainian Volunteer Corps as the Right Sector's own volunteer battalion. Unlike other far-right formations, such as the Azov Battalion and Sich Battalion, or the "Dnipro-1" which "Dnipro-2" was named after, the Volunteer Corps weren't intended to be subordinate to the Ministry of Internal Affairs as a "Special Tasks Patrol Police", but to operate independently. This was caused by a distrust of the Ministry after Right Sector activist Aleksandr Muzychko was shot dead by the Militsiya. On July 17, the first orders were given and the official statute was issued, and this is considered the official date of the formation of the Corps.

The Ukrainian Volunteer Corps went to the front in the Donetsk Oblast, where they had their baptism of fire at the Battle in Shakhtarsk Raion when they captured the town of Avdiivka from the Russian separatist forces in Donbas together with the 93rd Mechanized Brigade. Later in 1 August, the Volunteer Corps together with the 51st Guards Mechanized Brigade took the town of Krasnohorivka.