Jacob Klein

• Jacob Theodor Klein, Royal Prussian jurist, historian, botanist, mathematician and diplomat
• Jacob Herman Klein , Dutch composer
• Jacob [Klein (philosopher)], German-American philosopher and interpreter of Plato
• Jacob Klein (Assyriologist), Professor Emeritus of Assyriology and the Bible at Bar-Ilan University; member of Israel [Academy of Sciences and Humanities]
• Jacob Klein (chemist), soft condensed matter, polymer and surface scientist