Brendan John Frey FRSC (born 29 August 1968) is a Canadian-born machine learning and genome biology researcher, known mainly for his work on factor graphs, the wake-sleep algorithm for deep learning, and using machine learning to model genome biology and understand genetic disorders. He founded Deep Genomics and is currently its CEO, and he is a Professor of Engineering and Medicine at the University of Toronto. He co-developed a new computational approach to identifying the genetic determinants of disease, was one of the first researchers to successfully train a deep neural network, and was a pioneer in the introduction of iterative message-passing algorithms.