Samantha Smith came to fame by writing a letter to the Soviet leader, Yuri Andropov, in December 1982, expressing her fears about a potential nuclear war between the two superpowers. Her letter was quoted in the main Soviet newspaper Pravda in April 1983 and the Smith family was subsequently invited to visit the Soviet Union during the summer. Samantha’s trip captured the attention of the world media on both sides of the ideological divide. However, her trip has usually been dismissed as a quirky footnote in Cold War history. Scholarly interest has only just begun, sparked by the growing research into the significance of citizen diplomacy, which saw a real explosion in the late Cold War. This article will demonstrate that Samantha Smith’s trip was a pivotal moment in this broader process because it provided a very public challenge to the strong political discourse of the early Reagan administration, which promoted conflict. Based on an analysis of Soviet and American media reporting, and using hitherto unused archival evidence, as well as oral history interviews, this article examines why and how Samantha Smith became an icon of citizen diplomacy in the early 1980s. Analysing the receptions, representations and legacies of her trip on both sides of the ideological divide, it will shed fresh light on the role of children as soft power during the Cold War and highlight Samantha Smith’s role as a precursor of a rapidly expanding citizen diplomacy that played a largely ignored part in bringing the conflict to an end.