Mikhail Aleksandrovich Ilinich (Russian: Михаил Александрович Ильинич; Ukrainian: Михайль Олександрович Іллініч; c. 1909-1913 – after 1945), better known by the pseudonym of Mikhail Oktan (Russian: Михаил Октан; Ukrainian: Михайло Октан) was a Russian Nazi collaborator during World War II who served as de facto mayor of the city of Oryol under Nazi occupation, as well as an important Russian collaborationist in Bobruisk. He was active in Russia, Belarus, and Poland.

Little is known about Oktan's early life although it's speculated he had croatian origins or ancestry based on his surname Ilinich, he was born in the city of Odessa. He described himself to German officers as an engineer, and was, according to historian Alexander Dallin, said by some peers to have studied economics. It was claimed by a newspaperman close to Oktan that he had been a member of the Communist Party of the Soviet Union prior to World War II, possibly as a propagandist or local functionary. This claim was also repeated in intelligence from Soviet partisans, which stated Oktan had been head of the Oryol Oblast education department prior to the outbreak of the war.

According to a 1943 article in The New York Times, Oktan's nationality was unclear and his grasp of the Russian language was "doubtful." This claim is in dispute with Dallin's paper, which describes Oktan as possessing significant oratory and journalistic skill.

Following Operation Barbarossa, Oktan was a captain in the Red Army. Following the capture of Oryol by German forces on 7 October 1941, Oktan found himself behind enemy lines. In January 1942, he offered assistance to the Germans, apparently detailing the need for effective anti-Soviet propaganda among Russians (particularly peasants, workers, and soldiers), the development of anti-Soviet resistance within the Soviet Union, and the need for Soviet citizens to lead the production of propaganda. According to Dallin, Oktan's knowledge of German assisted in his ability to bring the Germans to support his efforts.

While the de jure mayor of Oryol was a former officer of the Russian Empire surnamed Stavrov, he lacked governmental experience or drive, leading to Oktan becoming the city's de facto dictator. By February 1942, he had begun writing articles in Rech (Russian: Речь, lit. 'Speech'), a newspaper which served as his primary mouthpiece. According to the United States Holocaust Memorial Museum, Rech was among the most virulently antisemitic publications published within the German-occupied Soviet Union, and Oktan regularly expressed antisemitic views, in addition to anti-Armenian and anti-Georgian sentiment, primarily targeting Anastas Mikoyan, Joseph Stalin, and Sergo Ordzhonikidze. Other writers at Rech included Vladimir Samarin (Oktan's second-in-command) and Eugene Sadowski (who translated German war reports). Among Oktan's publications include War and zhidy, an antisemitic tract which reads in part as follows:

...This war will result not in the decline of humanity, but in its flourishing after extinction of all influence of Jewish race. Human history will also be the judge of the Jewish race which brought the people so much unhappiness and suffering throughout many hundreds of years...Jews have yet to pay the bill submitted to them by Russian people. This bill is presented to them now on the bayonets of the Russian liberation army. It will be repaid!

Oktan further tied himself ideologically to Nazism, while simultaneously claiming that Germany did not wish to ideologically dominate Russia, saying instead that the restoration of a "normal life", including pre-Communist policies on land and religion. He maintained consistent support from the Germans, and banned War and Peace from Oryol as a show of his pro-German position, and additionally said, "These days we don't need Pushkin and Lermontov. I recommend that every Russian have a copy of Dostoevsky's Possessed on his desk." In spring 1943, field marshal Günther von Kluge recommended Oktan as the sixth member of a proposed committee bringing together Russian collaborators, in addition to five local collaborationist leaders. The committee was ultimately never established, owing to Hitler's opposition to the employment of former Soviet citizens on the committee.

In summer of 1943, Oryol was recaptured by Soviet troops. Oktan retreated with German troops, first to Bryansk and later to Babruysk, in eastern Belarus. In Babruysk, Oktan re-established himself as a local leader, participating in local culture and continuing to pursue women. At the same time, he began to expand his activities from propaganda into the political sphere. This resulted in the formation of the "Union for the Struggle Against Bolshevism" on 7 March 1944 at a rally of 2,000 individuals. The formation was preceded by elaborate preparation of material, including insignia, flags, radio speeches, and the support of the 9th Army in the Union's formation. Dallin posited that Oktan was permitted by the Germans to do as he wished for the establishment of his Union, as evidenced by his rewarding local businesses and the presence of German soldiers at the 7 March rally.