This is lecture notes on the course ‘Stochastic Processes’. In this format, the course was taught in the spring semesters 2017 and 2018 for third-year bachelor students of the Department of Control and Applied Mathematics, School of Applied Mathematics and Informatics at Moscow Institute of Physics and Technology. The base of this course was formed and taught for decades by professors from the Department of Mathematical Foundations of Control A.A. Natan, S.A. Guz, and O.G. Gorbachev. Besides standard chapters of stochastic processes theory (correlation theory, Markov processes) in this book (and lectures) the following chapters are included: von Neumann-Birkhoff-Khinchin ergodic theorem, macrosystem equilibrium concept, Markov Chain Monte Carlo, Markov decision processes and the secretary problem.