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