Ryszard Siwiec (Polish pronunciation: [ˈrɨʂart ˈɕivjɛt͡s]; 7 March 1909 – 12 September 1968) was a Polish accountant and former Home Army resistance member who was the first person to die by self-immolation in protest against the Warsaw Pact invasion of Czechoslovakia. Although his act was captured by a motion picture camera, Polish press omitted any mention of the incident, which was successfully suppressed by the authorities. Siwiec prepared his plan alone, and few people realized what he tried to achieve with his sacrifice. His story remained mostly forgotten until the fall of communism, when it was first recounted in a documentary film by Polish director Maciej Drygas. Since then, Siwiec has been posthumously awarded a number of Czech, Slovak, and Polish honours and decorations.

Siwiec's death preceded the much better known self-immolation of Jan Palach in Prague four months later. Siwiec was the first person from Central and Eastern Europe to self-immolate in protest of the invasion.

Siwiec was born in Dębica on 7 March 1909, under the Austrian Partition of Poland, then part of Austria-Hungary. He graduated from the Lwów University with a degree in philosophy. Siwiec worked as an accountant since the 1930s in Przemyśl, where he moved shortly after graduation. During World War II he escaped forced labour for the Germans by taking employment as a gardener and joined the Armia Krajowa (Home Army), the Polish resistance movement. Ryszard Siwiec married in 1945 and had five children.

According to friends and family, he had extensive historical knowledge and was deeply disillusioned with the reality of communist Poland. He supported the protesting students during the March 1968 Polish political crisis in Poland, printing bibuła leaflets and asking his daughter to distribute them. According to health professionals, he was of sound mind, and fully rational, at the time of his suicide. Siwiec planned his self-immolation months in advance, writing out a last will in April, and leaving written and tape-recorded statements explaining his revulsion at both the Warsaw Pact invasion of Czechoslovakia and the Polish People's Republic's participation in it.

Siwiec obtained passes to a national harvest festival taking place on 8 September 1968 at the 10th-Anniversary Stadium in Warsaw. His goal was to have his act be witnessed by nearly 100,000 spectators, including numerous journalists and the national leadership of the Polish United Workers' Party. He set himself ablaze during one of the festival dances using a flammable solvent. This method of protest was likely inspired by recent series of similar protests by Buddhist monks in Vietnam, most notably that of Thích Quảng Đức. He had a banner with the words "For our freedom and yours" and "Honour, Fatherland" as well as some leaflets, which he is said to have thrown around right before the incident, though neither attracted much attention, and both items are primarily mentioned only in the documents of the investigating secret police. He refused immediate help and shouted "I protest". He retained consciousness after the flames had been extinguished, giving brief statements, as well as later when he was transferred to a hospital (Szpital Praski), where he was able to communicate with the medical personnel, and where he received a brief visit from his wife. In the hospital, he was put under police surveillance, dying four days later on 12 September.

The incident was immediately suppressed by the authorities. A story invented on the spot was that it was an accident caused by drinking vodka and smoking, or spontaneously combusting, aiming to divert interest to gossip and portray Siwiec as an irresponsible drunk. He was also declared mentally ill.

Despite many attendees at the festival, there were relatively few witnesses, and the incident did not cause any delay in the main proceedings. Journalists and others knew that they would not be able to publish any photographs or movies, so those aware of the incident did not bother recording it other than by accident, nor did any try to investigate it afterward. Most of the few photographs of the incidents have been destroyed or forgotten and lost. Siwiec was censored out of official photographs of the Central Photographic Agency (Centralna Agencja Fotograficzna), which had a monopoly on issuing photos for the press in the era of communist Poland. His act was captured in a 7-second film by a motion picture camera of the Polish Film Chronicle, but the official newsreels of the festival omitted any mention of the incident. This footage however survived, mislabeled either by accident or purpose, until it was rediscovered over twenty years later.

Polish secret police (Służba Bezpieczeństwa) made a routine investigation that ended quickly due to the "death of the culprit", followed by routine low-key surveillance of his friends and family, during which it intercepted Siwiec's last letter to his wife (delivered decades later). Overall, the authorities had little trouble suppressing the events, as none of the relatively few witnesses have shown any particular desire to make the event more widely known. There was some gossip about the incident, with most people considering it a suicide rather than an accident, but the reason for it was unclear, and no one connected Siwiec's dramatic actions to contemporary political events. As publicist Stefan Kisielewski wrote in his diary two days after Siwiec's death, "There are rumours about a self-immolation [during the festival] but none knows the reason for it."