A lynching postcard is a postcard bearing the photograph of a lynching—a vigilante murder usually motivated by racial hatred—intended to be distributed, collected, or kept as a souvenir. Often a lynching postcard would be inscribed with racist text or poems. Lynching postcards were in widespread production for more than fifty years in the United States, although their distribution through the United States mail was banned in 1908.

Terror lynchings as a display of racial domination peaked around the 1880s through to the 1940s, and were less frequent until the 1970s, especially (but not exclusively) in the Southern United States. Lynchings were widely used to intimidate recently emancipated African Americans after the Civil War Reconstruction era, and were later used to intimidate voters and civil rights workers of all ethnic backgrounds. Mostly African-American men, women, and children were lynched, for a lack of subservience or for success in business. Others were often accused of crimes and forcibly removed from their homes or jails to be murdered by a white supremacist mob without due process or presumption of innocence.

Spectators sold one another souvenirs including postcards. Often the photographer was one of the killers.

In a typical lynching postcard, the victim is displayed prominently at the center of the shot, while smiling spectators, often including children, crowd the margins of the frame, posing for the camera to prove their presence. Facial expressions suggesting remorse, guilt, shame, or regret are rare.

Some purchasers used lynching postcards as ordinary postcards, communicating unrelated events to friends and relatives. Others resold lynching postcards at a profit. Still others collected them as historical objects or racist paraphernalia: their manufacture and continued distribution was part of white supremacist culture, and has been likened to "bigot pornography".

Whatever their use, the cultural message embodied in most lynching postcards was one of racial superiority. Historian Amy Louise Wood argues:

Within specific localities, viewers did not disconnect the photographs from the actual lynchings they represented. Through that particularity, the images served as visual proof for the uncontested 'truth' of white civilized morality over and against supposed black bestiality and savagery.

Viewed from an outsider's perspective, bereft of local context, the postcards symbolized white power more generally. White citizens were depicted as victorious over powerless murdered black victims, and the pictures became part of secular iconography.