Ewald Rudolf Weibel HonFRMS (5 March 1929 – 19 February 2019) was a Swiss anatomist and physiologist and former director of the Institute of Anatomy at the University of Bern.

He was one of the first scientists to describe the endothelial organelles Weibel–Palade bodies, which are named after him and his Romanian-American colleague George Emil Palade.

[1] He was known for his work on the anatomy of gas exchange in lungs on multiple spatial scales using stereology.

From 1979 until 1996 he was Visiting Agassiz Professor and Associate in the Museum of Comparative Zoology at Harvard University.

[4] His scientific work covered four main areas: the morphometry of the human lung as the structural basis of the gas exchange function; the development of morphometric and stereological methods; the application of these methods in cell biology to measure the membrane system of the liver cell and the mitochondria in the muscles; integrative studies in comparative physiology, particularly on the question of the optimal structural basis of the organismic functions of the respiratory system, from the lungs to the muscle cells and their mitochondria, based on the hypothesis of symmorphosis.