Touko Valio Laaksonen (8 May 1920 – 7 November 1991), known by his pseudonym Tom of Finland, was a Finnish artist who made stylized erotic art featuring suggestively hypermasculine male characters. He worked primarily in pencil, producing drawings on paper and for publication in a variety of magazines and other formats. These works profoundly influenced late 20th-century gay culture and sexuality, their rise in popularity coinciding with gay law reform successes and the cultural and political emergence of LGBTQ+ communities from the 1960s onward. Tom of Finland has been called the "most influential creator of gay pornographic images" by cultural historian Joseph W. Slade. Over the course of four decades, he produced some 3,500 illustrations, mostly featuring men with exaggerated sexual traits, wearing tight or partially removed clothing. In 1984, he founded the Tom of Finland Foundation to preserve his catalogue of works and support erotic art generally; it continues to operate from TOM House in Los Angeles.

Laaksonen was born on 8 May 1920 and raised by a middle-class family in Kaarina, a town in southwestern Finland, near the city of Turku. Both of his parents Suoma and Edwin Laaksonen were schoolteachers at the grammar school that served Kaarina. The family lived in the school building's attached living quarters.

He went to school in Turku and in 1939, at the age of 19, he moved to Helsinki to study advertising. In his spare time he also started drawing erotic images for his own pleasure, based on images of male laborers he had seen from an early age. At first he kept these drawings hidden, but then destroyed them "at least by the time I went to serve the army." Finland became embroiled in the Winter War with the Soviet Union, and then became formally involved in World War II, and he was conscripted in February 1940 into the Finnish Army. He served as an anti-aircraft officer, holding the rank of second lieutenant. He later attributed his fetishistic interest in uniformed men to encounters with men in army uniform, especially soldiers of the German Wehrmacht serving in Finland at that time. He said, "In my drawings I have no political statements to make, no ideology. I am thinking only about the picture itself. The whole Nazi philosophy, the racism and all that, is hateful to me, but of course I drew them anyway—they had the sexiest uniforms!" After the war, in 1945, he returned to studies.

Laaksonen's artwork of this period compared to later works is considered more romantic and softer with "gentle-featured shapes and forms". The men featured were middle-class, as opposed to the sailors, bikers, lumberjacks, construction workers, and other members of stereotypically hypermasculine working class groups that feature in his later work. Another key difference is the lack of dramatic compositions, self-assertive poses, muscular bodies, and "detached exotic settings" that his later work embodied.

In 1956 Laaksonen submitted drawings to the American magazine Physique Pictorial, which premiered the images in the 1957 Spring issue under the pseudonym Tom, as it resembled his given name Touko. In the Winter issue later that year, editor Bob Mizer coined the credit Tom of Finland. One of his pieces was featured on the Spring 1957 cover, depicting two log drivers at work with a third man watching them. Inspired by lumberjacks representing strong masculinity in Finnish culture, Laaksonen emphasized "homoerotic potentiality [...] relocating it in a gay context", a strategy repeated throughout his career.

The post-World War II era saw the rise of the biker subculture as rejecting "the reorganisation and normalisation of life after the war, with its conformist, settled lifestyle." Biker subculture was both marginal and oppositional, and provided postwar gay men with a stylised masculinity that included rebelliousness and danger. This was in contrast to the then-prevailing stereotypes of the gay man as effeminate (sissy), as seen in vaudeville and films going back to the first years of the industry. Laaksonen was influenced by images of bikers as well as artwork of George Quaintance and Etienne, among others, that he cited as his precursors, "disseminated to gay readership through homoerotic physique magazines" starting in 1950. Laaksonen's drawings of bikers and leathermen capitalized on the leather and denim outfits, which differentiated those men from mainstream culture and suggested they were untamed, physical, and self-empowered. This contrasted with the mainstream, medically and psychologically sad and sensitive young gay man who is passive. Laaksonen's drawings of this time "can be seen as consolidating an array of factors, styles and discourses already existing in the 1950s gay subcultures," which may have led to them being widely distributed and popularized within those cultures. He worked at an advertising agency in the 1960s.

Laaksonen's style and content in the late 1950s and early 1960s was partly influenced by the U.S. censorship codes that restricted depiction of "overt homosexual acts". His work was published in the beefcake genre that began in the 1930s and predominantly featured photographs of attractive, muscular young men in athletic poses often shown demonstrating exercises. Their primary market was gay men, but because of the conservative and homophobic social culture of the era, gay pornography was illegal and the publications were typically presented as dedicated to physical fitness and health. They were often the only connection that closeted men had to their sexuality. By this time, however, Laaksonen was rendering private commissions, so more explicit work was produced but remained unpublished. Aside from his work at an advertising agency, Laaksonen operated a small mail-order business, distributing reproductions of his artwork around the world by post, though he did not generate much income this way.

In the 1962 case of MANual Enterprises v. Day the United States Supreme Court ruled that nude male photographs were not inherently obscene. Softcore gay pornography magazines and films featuring fully nude models, some of them tumescent, quickly appeared and the pretense of being about exercise and fitness was dropped as controls on pornography were reduced. By the end of the 1960s the market for beefcake magazines collapsed. Laaksonen was able to publish his more overtly erotic work and it changed the context with "new possibilities and conventions for displaying frontal male nudity in magazines and movies." Laaksonen reacted by publishing more explicit drawings and stylized his figures' fantastical aspects with exaggerated physical aspects, particularly their genitals and muscles. In the late 1960s he developed Kake, a recurring fictional character that appeared in 26 comics from 1968 to 1986.