John Roger Speakman (born 1958) FRS FRSE FRSB FRSA FMedSci FRSS is a British biologist working at the University of Aberdeen, Institute of Biological and Environmental Sciences, for which he was Director from 2007 to 2011. He leads the University's Energetics Research Group, which is one of the world's leading groups using doubly labeled water (DLW) to investigate energy expenditure and balance in animals. Between 2011-2020, he was a '1000 talents' Professor at the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, in Beijing, China, where he ran the molecular energetics group. In 2020 he moved to the Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences in Shenzhen, China where he works at the Center for Energy Metabolism and Reproduction and