The 3rd Separate Assault Brigade (Ukrainian: 3-тя окрема штурмова бригада, romanized: 3-tya okrema shturmova bryhada) is a brigade of the Ukrainian Ground Forces formed in 2022.

The brigade was established by a merger of the Azov SSO (Special Operations Forces) units that had been created by former Azov Battalion veterans. The brigade is commanded by Andriy Biletsky, founder and former commander of the Azov Battalion and former People's Deputy of Ukraine.

With the start of the Russian invasion of Ukraine in 2022, most units of the Azov Regiment were based in Mariupol where they soon would be besieged. Outside of Mariupol, many former veterans of Azov outside the city began forming new units, in particular in Kyiv, Sumy and Kharkiv. These units were soon integrated into the Special Operations Forces (SSO) of the Armed Forces of Ukraine, and became collectively known as "Azov SSO".

In January 2023, all the former Azov SSO were merged into a single fully operational combat unit within the Ukrainian Ground Forces of the Armed Forces of Ukraine. The formation of this brigade was strategically designed to create a highly mobile, well-equipped, and extensively trained force capable of engaging in both defensive and offensive operations.

An important milestone for the brigade occurred on 24 February 2023, when President Volodymyr Zelenskyy personally presented the Regimental Colour during a ceremonial event. The colors of the brigade were said to "symbolize the tenacity of the traditions of Ukrainian statehood; from precisely the times of the Kievan Rus', the Cossack period, the first liberation struggles in the early 20th century to modern times.

The brigade's soldiers took part in the liberation of Kherson and parts of the Kherson Oblast, as well as in the battle of Bakhmut. On April 12, 2023, the brigade's official media resources announced the start of recruitment efforts. In May 2023, it was one of the first to report successful offensives in the Bakhmut district against the Russian Ground Forces.

On 15 September 2023, after months of fighting, the brigade liberated Andriivka, and held onto it despite a Russian counterattack on 17 September. Ukrainian ground forces commander General Syrskyi called Klishchiivka and Andriivka "important elements of the Russian Bakhmut-Horlivka defensive line", and ISW assessed that the capture of these settlements defending a key Russian ground line of communication will make it difficult for the already weary defending forces to replenish and continue defending.

In February 2024, shortly after the dismissal of Zaluzhnyi, the brigade was transferred into Avdiivka to relieve the potential encirclement of the city. After the fall of Avdiivka on February 17, the brigade took new defensive lines west of Avdiivka around Lastochkyne. On 17 February, the brigade's press officer, Oleksandr Borodin, claimed that during its relocation to Avdiivka, his unit had killed 1,500 Russians, wounded over 3,500, and destroyed 20 armoured vehicles. He also said that the brigade has "no reports" of large numbers of their soldiers being taken prisoner.

On 27 May 2024, the brigade claimed to have killed, wounded or taken prisoner "close to" 600 Russian troops in Kharkiv Oblast. One Russian soldier captured by the brigade claimed in an interview that he was the only survivor of his 15-man section following an attack. On 19 June, the brigade claimed that their 1st Mechanised Battalion had killed 250 Russians in Kharkiv Oblast, publishing a video that purportedly proved their claims.

On 22 August 2024, the brigade claimed to have taken two square kilometers in a counterattack against Russia's 20th Army in Kharkiv Oblast. Despite being outnumbered 2.5 to 1, they claimed to have defeated a battalion, including "platoon and company strong points", killing 300 personnel in three days and diverting Russian forces away from Makiivka.

According to the independent French investigative online newspaper Mediapart, the French army trained soldiers from the 3rd Assault Brigade at the La Courtine camp, in the Creuse in 2023. Several of them displayed neo-Nazi symbols and on their social network profiles, including "Hitlerian salutes, Celtic crosses, emblems of several SS divisions, skulls, pictures of Adolf Hitler". Mediapart asked the French Ministry of the Armed Forces to comment on the matter. The response was "It is the Ukrainian armed forces that organise the flow and selection of Ukrainian soldiers sent to France and Europe. We therefore have no comment to make on this organisation." The Politician Catherine Couturier protested against the Ministry of the Armed Forces.

In 2022, the Canadian Army was also criticised for training soldiers of the 3rd Assault Brigade.

In July 2024, the brigade organised a tour through Europe to recruit volunteers and promote their image. After protests from left-wing groups, especially in Germany, events in Berlin, Hamburg, Rotterdam, Cologne and Brussels were cancelled. The Bündnis Sahra Wagenknecht party declared that "The fact that such a war glorification event could take place in Berlin, particularly by an openly right-wing extremist organisation that historically refers to the Nazi collaborator Stepan Bandera, is an incredible scandal." There were also protests over the tour in Prague.

According to some German daily newspapers, in July 2024, a Ukrainian soldier of the 3rd Assault Brigade visited the Auschwitz concentration camp wearing a T-shirt from the neo-nazi black metal band "M8l8th" ("88" is an abbreviation for "Heil Hitler"), active in Ukraine from 2014, with the inscription "Where we are, there is no place for anyone else"; a quote that, according to historians, could be attributed to Adolf Hitler. The spokesman for the Auschwitz Museum stated that they "will inform both the Polish prosecutor's office and the Embassy of Ukraine in Warsaw about this painful incident related to hate speech". According to Polish Press Agency the quote mentioned does not belong to Hitler, the identity of the man is unknown, the photo was originally published on Russian propaganda social accounts where Kremlin propaganda presents Mariupol defenders as neo-Nazis, and is likely a Russian provocation aimed to convince that the declared goal of "denazification of Ukraine" of the Russian invasion of Ukraine is justified.

As of 2024, the brigade's structure is as follows: