B. Adolf Kratzer (October 16, 1893 – July 6, 1983) was a German theoretical physicist who made contributions to atomic physics and molecular physics, and was an authority on molecular band spectroscopy. He was born in Günzburg and died in Münster. Kratzer published a number of physics books, based on his lectures on electrodynamics, mechanics, optics, relativity, thermodynamics, and quantum mechanics (wave mechanics). A book on transcendental functions was written with Walter Franz, also a student of Sommerfeld.