Lithuanian Activist Front or LAF (Lithuanian: Lietuvos Aktyvistų Frontas) was a short-lived resistance organization established in 1940 after Lithuania was occupied by the Soviet Union. The goal of the organization was to liberate Lithuania and re-establish its independence.

It planned and executed the June Uprising and established the short-lived Provisional Government of Lithuania. The Government self-disbanded and LAF was banned by Nazi authorities in September 1941. LAF remains rather controversial due to its anti-Semitic and anti-Polish views. LAF was established on 17 November 1940.

 Kazys Škirpa, former Lithuanian military attaché to Germany, is often credited as the founder.

 LAF was meant to unite people of various political beliefs, who wanted to see Lithuania as an independent country, rather than as part of the Soviet Union or Nazi Germany. The Berlin unit, formed by Kazys Škirpa, united mainly former Lithuanian expatriates and diplomats in Germany. It gathered representatives of most major pre-war Lithuanian factions and parties, and within LAF, the most influential were the Nationalist Unionists and the Christian Democrats.

 As time passed, local LAF units were formed in various Lithuanian cities. The local LAF units were organizing espionage networks.

 The local LAF units in Lithuanian cities maintained more liberal political views than the Berlin headquarters. Lack of correspondence between the Berlin unit and Lithuanian units prevented discussions of ideology. In Germany, LAF had contact with Wilhelm Franz Canaris andAbwehr, but not the Nazi party.[citation needed] LAF expected that Nazi Germany would attack the Soviet Union and planned to use this occasion for their own rebellion and establishment of independent Lithuania. On 22 April 1941, representatives of Vilnius and Kaunas branches of LAF formed the Provisional Government of Lithuania, i.e. established a list of its members.  

LAF formed the Lithuanian underground government planning to take over the country when the Soviet army would be pushed out by the German army. The Provisional Government was mainly formed out of Vilnius and Kaunas sections of LAF. However, two of its members, including the prime minister Kazys Škirpa, were in Germany and were later detained there. Over time, many people from this government, as well as other LAF members, were arrested, executed, or exiled by Soviet authorities.  

Germany declared war on the Soviet Union on June 22, 1941, and the same day LAF started the June Uprising. LAF partisans aided the Germans.

The next day, June 23, independence of Lithuania was declared.   Short-handed Provisional Government took power on June 24.

On June 21 four members of the government were arrested by the Soviet authorities, supposed prime minister Kazys Škirpa was put under house arrest in Berlin, and another minister was also unable to come. Juozas Ambrazevičius became the prime minister.  

During this time, LAF called for creation of Ghettos for Poles, Polish identification badges similar to those required for Jews as well as lower food rations. Statements by LAF proclaimed that under the Soviets they managed to kill 50% of all Poles in Lithuania, and that under the Nazis they would kill the remaining 50%.

However, the negotiations with Germany over the recognition of Lithuania failed, as Nazi government had no interest in an independent Lithuania. The LAF government had strong support from Lithuanian people and the German authorities did not use brutal force against its members. Rather, they established their own administrative structures (Reichskommissariat Ostland) and slowly deprived the government of its powers. The government lost all of its power in a few weeks, and seeing no more reason to continue work, dissolved itself in August 1941.  

LAF as an organization remained. In September it sent a memorandum to Germany protesting against the occupation of Lithuania. In response, the Lithuanian Activist Front was banned on September 26; many of its leaders were arrested and sent to concentration camps.   LAF is claimed a controversial organization because of its anti-Semitic and anti-Polish views and overall collaboration with the Nazi Germany.

For example, LAF's manifesto-type essay  "What Are the Activists Fighting for?" states:  

"The Lithuanian Activist Front, by restoring the new Lithuania, is determined to carry out an immediate and fundamental purging of the Lithuanian nation and its land of Jews ...".  

When the June uprising began in the Polish-majority Vilnius Region, the LAF committed many atrocities (rapes, murders, pillage); even the Germans referred to their "allies" as "organized robbers". Also, a number of LAF government acts discriminated against Jews, one notable example being "Žydų padėties nuostatai" (English: Regulation on Status of Jews).

LAF however did not support and unsuccessfully attempted to stop pogrom organized by Algirdas Klimaitis in Vilijampolė.