Fritz Walther Meißner (anglicized: Meissner) (16 December 1882 – 16 November 1974) was a German technical physicist.

Meißner was born in Berlin to Waldemar Meißner and Johanna Greger. He studied mechanical engineering and physics at the Technische Hochschule in Charlottenburg (now Technische Universität Berlin), his doctoral supervisor being Max Planck. He then entered the Physikalisch-Technische Bundesanstalt in Berlin. From 1922 to 1925, he established the world's third largest helium-liquifier, and discovered in 1933 the Meissner effect, damping of the magnetic field in superconductors. One year later, he was called as chair in technical physics at the Technical University of Munich.

After World War II, he became the president of the Bavarian Academy of Sciences and Humanities. In 1946, he was appointed director of the academy's first low temperature research commission. Laboratories were located in Herrsching am Ammersee until 1965, when they were moved to Garching. Meißner lived alone with his two dogs for the last several years of his life. Meißner died in Munich in 1974.