Steven Victor Ley CBE FRS FRSC (born 10 December 1945) is Professor of Organic Chemistry in the Department of Chemistry at the University of Cambridge, and is a Fellow of Trinity College, Cambridge. He was President of the Royal Society of Chemistry (2000–2002) and was made a CBE in January 2002, in the process. In 2011, he was included by The Times in the list of the "100 most important people in British science".^[5][6][7][8]

Ley was educated at Stamford and Loughborough University of Technology where he was awarded a Bachelor of Science and PhD.^[4][2]

Ley's main research field are the total synthesis of biomolecules. His group has published extensively on this topic, and has completed the synthesis of more than 140 natural target compounds, with notable examples including indanamycin, routiennocin, avermectin B1a, okadaic acid, spongistatin, thapsigargin, epothilone A, antascomicin B, bengazole A and rapamycin. His total synthesis of azadirachtin, completed in 2007, is widely regarded as one of the major landmarks in total synthesis. In the course of this work, he has also made substantial advances in many areas of organic chemistry, including the development of new catalysts, protecting groups and reagents. He is one of the inventors of TPAP, a widely employed oxidising reagent. He has also pioneered the use of immobilised reagents and flow techniques in multi-step organic synthesis. This work now incorporates flow chemistry for multistep organic synthesis applications.

By 2020, Ley had published 888 academic research papers spanning his career of 50 years.^[9]

As of 2022, Ley's work of over 900 papers^[10][11] has been recognised by about 45 major prizes and awards, including: