Oksana Akinshina was born on April 19, 1987, in Leningrad into a family of ordinary parents. Her father was a car mechanic and her mother an accountant. Oksana also has a younger sister whose name is unknown. From a very early age, the girl witnessed numerous quarrels between her parents and was practically left to her own devices, which undoubtedly could not but affect her character, and not in the best way. She treated her mother more tenderly, though she perceived her more as a friend. Having received enormous freedom in childhood, she often disregarded social norms, trying to express herself and show that she was not like everyone else. The actress also had problems with alcohol. She underwent treatment for a long time, resorting to various methods to get rid of the harmful habit. "At first it was unbearable. A psychologist helped, then there was a pill, then I had my coding removed. Now I have been taught to pull myself together at almost any moment. But pulling yourself together in some states is very disgusting. I would even say that I feel squeamish about pulling myself together," she said. Already at the age of thirteen, Oksana got a job at a modeling agency. It was through it that she ended up at the casting for Sergei Bodrov Jr., who was just then selecting actors for the film "Sisters." Oksana went there without much enthusiasm, expressing her dissatisfaction everywhere, since it was an obligation from the director of the modeling agency. But the girl's bold and unruly nature appealed to the young director, and Oksana was approved for the role of the elder of the sisters. For their roles in this film, Oksana Akinshina and Katya Gorina received the award "For Best Acting Duo" in the "Debut" competition at the Sochi film festival "Constellation," as well as a prize at the "Kinotavr" festival for "Best Acting Duo" in 2001. In the same year, Oksana received a prize at the All-Russian Festival of Visual Arts for "Best Female Role." Outside Russia, Oksana Akinshina became known thanks to her participation in the film by Swedish director Lukas Moodysson, "Lilya 4-Ever," who was delighted by Oksana's performance in "Sisters" and without much hesitation invited her for the role, even though she did not fit the original image of the main character. For it, in 2002, Oksana received a prize at the thirteenth International Film Festival in Stockholm in the nomination "Best Female Role," the Swedish Film Academy film award "Golden Beetle" in the nomination "Leading Female Role," and the audience choice award in the competition "Best Actress of Sweden." In 2003, Oksana starred in the Dutch film "South," where she played a young single mother who illegally arrived in Holland. For the filming of the film, Oksana even had to study the basics of the Dutch language. In the same year, she received the prize "Best Young Promising Actress" at the third European Film Festival in Stuttgart.

In 2016, she starred in the comedy "SuperBobrovy" by director Dmitry Dyachenko, in which Oksana Akinshina played the main role together with Pavel Derevyanko.