John of Tynemouth was a 13th-century mathematician and geometer. Little is known of John's background, but he authored De curvis superficiebus or Liber de curvis superficiebus Archimenidis, a tract about Archimedes' measurements of spheres. This is an important work in the history of medieval geometry, as it helped transmit Archimedes' ideas to other medieval scholars. The work itself follows closely Archimedes' own reasoning, but with enough differences to lead modern historians to believe that John's work was dependent on a Greek text from late antiquity.