Ewald may refer to any of the following people and concepts:
- People
- Either of the two saints named Ewald, martyrs in Old Saxony about 695
- Carl Anton Ewald, a pioneering German gastroenterologist
- Johann Ewald, a Danish general and veteran of the American Revolutionary War
- Johannes Ewald, a Danish dramatist and poet
- Heinrich Ewald, a German orientalist and theologian
- Paul Peter Ewald, a pioneer of X-ray diffraction and crystallography
- Paul W. Ewald, the evolutionary biologist specializing in the evolution of infectious disease
- Victor Ewald, the Russian composer
- Ewald Stadler (born 1961), Austrian politician
- Concepts
- Ewald's sphere, a geometric construct used in crystallography
- The Ewald summation, a method for computing the interaction energies of periodic systems