Thomas Platter the Younger (; German: [ˈplatɐ]; c. 24 July 1574 in Basel – 4 December 1628 in Basel) was a Swiss-born physician, traveller, and diarist, the son of the humanist Thomas Platter the Elder. He was a professor of anatomy, botany, and medicine at the University of Basel, as well as the city physician for Basel.
Platter kept a diary from 1595 to 1600. Platter recounts his life as a medical student in Montpellier and his travels in France, Spain, Flanders, and England. He describes many aspects of late sixteenth-century European culture: medical education (including dissections), street and carnival life in Barcelona, European theater, and the slave trade.
On 21 September 1599, "at about two o'clock," Platter and his older half-brother Felix Platter saw an early production of Julius Caesar at the Globe Theatre in London. Platter's account provides Shakespeare scholars with evidence for the dating of that play.
Ladurie, Emmanuel Le Roy; Liechtenhan, Francine-Dominique (2000). Le voyage de Thomas Platter 1595-1599. (Le siècle des Platters II). Paris: Fayard. ISBN 2213605475.
Ladurie, Emmanuel Le Roy; Liechtenhan, Francine-Dominique (2006). L'Europe de Thomas Platter: France, Angleterre, Pays-Bas 1599-1600. (Le siècle des Platters III). Paris: Fayard. ISBN 2213627851.
Platter, Thomas (1968). Rut Keiser (ed.). Beschreibung der Reisen durch Frankreich, Spanien, England und die Niederlande (1595-1600). Basel, Stuttgart: Schwabe. ISBN 3796502067.
Platter, Thomas (1963). Journal of a Younger Brother: the Life of Thomas Platter as a Medical Student in Montpellier at the Close of the Sixteenth Century. Translated by Seán Jennett. London: Frederick Muller.
Platter, Thomas (1995). Razzell, Peter (ed.). The Journals of Two Travellers in Elizabethan and early Stuart England: Thomas Platter and Horatio Busino. London: Caliban. ISBN 185066014X.
Platter, Thomas (1937). Thomas Platter's Travels in England, 1599. Translated by Clare Williams. London: Jonathan Cape.