Otto Plattner was a Swiss painter, graphic artist and heraldist.

Otto Plattner was born in Liestal (Canton Basel-Landschaft) on June 29, 1886, the son of the merchant Wilhelm Plattner and Marie Plattner, née Strübin. He completed courses at the Allgemeine Gewerbeschule in Basel and was encouraged by Fritz Schider. He then did an apprenticeship as a decorative painter at the École des Beaux-Arts in Geneva. In 1910, Plattner was in Paris with Hermenegildo Anglada Camarasa and in Munich with Moritz Heymann.

In 1912, Plattner founded his own studio on Eichenstrasse in Basel. In the same year, he married Frida Lüdin from Liestal, the daughter of the bookseller Friedrich August Lüdin.

In addition to his free works and wall paintings, he was particularly interested in graphics and glass painting, as well as occasional Schnitzelbänke. He soon became a sought-after lantern painter for the Basel Carnival.

Study trips took him to Italy and Sicily in 1922, to Tunisia in 1926, to Italy and Cologne in 1933, to Upper Bavaria and to Hungary in 1935. In the mid-1930s, he took up residence in Liestal.

Otto Plattner died in Stein am Rhein on October 20, 1951 and was buried in the Liestal cemetery. Karl Aegerter delivered the eulogy on October 23, 1951. Thanks to a donation from the artist's daughter, Stefy Plattner, the majority of his estate is kept in the Liestal Museum of Literature and History.