The Bikiniarze (singular: bikiniarz , "bikini boys") were a youth subculture in Stalinist-era Poland, active from the late 1940s through the 1950s. They were defined by their flamboyant, Western-inspired fashion and a love for jazz music, which together served as a form of cultural rebellion against the gray, state-enforced uniformity of communism.

According to writer Leopold Tyrmand, their name originated from their iconic, hand-painted neckties, which often featured imagery related to the Bikini Atoll—such as palm trees, women in bikinis, and even atomic bomb mushroom clouds.

The movement was the Polish equivalent of similar post-war youth subcultures across Europe, such as the Stilyagi in the Soviet Union or the Zazou in France. Their aesthetic was a conscious rejection of socialist realist doctrine and a "small gesture of independence" in a time of repression.

The Bikiniarze subculture emerged in post-WWII Poland as a reaction against the drab reality of Stalinism. At a time when the communist authorities promoted an ascetic and uniform image for its citizens, the Bikiniarze manifested their individuality through fashion and music, drawing inspiration from an inaccessible, idealized American culture.

Their non-conformity was viewed by the authorities as an ideological threat. The Bikiniarze were subjected to a massive negative propaganda campaign in the state-controlled press, where they were portrayed as "hooligans," "parasites," and "enemies of the people," corrupted by "imperialist influences." The state organized crackdowns, and members of the subculture were regularly detained, beaten, and arrested by the Citizens' Militia ( Milicja Obywatelska ) and its volunteer reserve (ORMO).

The persecution culminated in a 1951 show trial of "bikiniarze," where young people were accused of espionage and sabotage, supposedly inspired by broadcasts from Radio Free Europe. The trial was a propaganda tool designed to discredit the movement and intimidate youth away from Western influences.

The fashion of the Bikiniarze was their primary tool of rebellion. Every element of their attire was carefully chosen to contrast with the socialist grayness of the streets.

The male uniform was built around a specific silhouette, featuring a wide, plaid jacket with padded shoulders (known as a marynara na kilowatach , "jacket on kilowatts") paired with very narrow, tapered trousers. The most iconic element was the hand-painted necktie, which was decorated with colorful, exotic motifs such as palm trees, women in bikinis, or mushroom clouds in a direct reference to the American nuclear tests on the Bikini Atoll. This look was completed with thick, crepe-soled suede shoes, colloquially called słonina ("lard"), which revealed brightly colored, striped socks known as piratki ("pirates"). Men wore their hair long and styled it into a signature wave combed back from the forehead, a look known as a mandolina ("mandolin") or kaczy kuper ("duck's ass").

Women associated with the movement, called kociaki ("kittens"), wore wide, circular skirts or very narrow pencil skirts with a slit, tight-fitting blouses, and, daringly for the time, trousers and leather jackets. Their simple ponytail hairstyles and use of makeup (red lipstick, defined eyebrows) also emulated the style of Western movie stars.