Lam Lay Yong (maiden name Oon Lay Yong, Chinese: 蓝丽蓉; pinyin: Lán Lìróng; born 1936) is a retired Professor of Mathematics. From 1988 to 1996 she was Professor at the Department of Mathematics, National University of Singapore. She graduated from the National University of Singapore (NUS) in 1957 and pursued graduate study in Cambridge University, obtaining her Ph.D. degree from University of Singapore in 1966, and becoming a lecturer at the University of Singapore. She was promoted to full professor in 1988, taught in NUS for 35 years, and retired in 1996.
From 1974 to 1990, Lam Lay Yong was the associate editor of Historia Mathematica. Lam was a member of Académie Internationale d'Histoire des Sciences.
In 2002, Lam Lay Yong was awarded the Kenneth O. May Prize for her contribution to the history of Mathematics. Lam is the first Asian and first woman to have won this highest award in the field of history of mathematics. In her reception speech, she delivered Ancient Chinese Mathematics and its influence on World Mathematics.
Lam Lay Yong also won the 2005 Outstanding Science Alumni Award from NUS. She is the granddaughter of Tan Kah Kee and niece of Lee Kong Chian,Jiu Zhang Suanshu (1994) "(Nine Chapters on the Mathematical Art): An Overview, Archive for History of Exact Sciences, vol. 47: pp. 1–51.
Zhang Qiujian Suanjing (1997) "(The Mathematical Classic of Zhang Qiujian): An Overview", Archive for History of Exact Sciences, vol. 50: pp. 201–240.
Lam Lay Yong, Ang Tian Se (2004) Fleeting Footsteps. Tracing the Conception of Arithmetic and Algebra in Ancient China, Revised Edition, World Scientific, Singapore.
Lam Lay Yong (1977) A Critical Study of the Yang Hui suan fa, NUS Press.
Lam Lay Yong, "A Chinese Genesis, Rewriting the history of our numeral system", Archive for History of Exact Science 38: 101–108.
Lam Lay Yong (1966) "On the Chinese Origin of the Galley Method of Arithmetical Division", The British Journal for the History of Science 3: 66–69 Cambridge University Press.
Lam Lay Yong (1996)  "The Development of Hindu-Arabic and Traditional Chinese Arithmetic", Chinese Science 13: 35–54.
Oon Lay Yong (2009) Arithmetic in Ancient China OCT .
Lam Lay-Yong and Shen Kangshen (沈康身) (1989) "Methods of solving linear equations in traditional China", Historia Mathematica, Volume 16, Issue 2, Pages 107–122.