Quantum Mechanics is a theoretical science that deals with the science of motion of microscopic particles like atomic and subatomic particles. Quantum Chemistry is a sub field of Quantum Mechanics that describes the behavior of electrons and their chemistry. The study of quantum chemistry is significant because the physicochemical properties of atoms and molecules, their structures, spectral properties and reactions may be interpreted in terms of motion of micro particles. This book is divided into 10 chapters. The different chapters includes: Fundamental Postulates of Quantum Mechanics, Particle in a box problem, Quantum Mechanical Tunneling, Harmonic Oscillator Model, Rotational Motion and Rigid Rotor Model, The Hydrogen Atom and Hydrogen-like systems, Electron Spin, Spin orbit interaction and term symbols. At the end of each chapter a good number of questions and problems are provided.