尼可拉斯·格里高利·曼昆（Nicholas Gregory "Greg" Mankiw，1958年2月3日－）是一位美国经济学家。1980年以最优等成绩毕业于普林斯顿大学，1984年在麻省理工学院获得博士学位，29岁时成为哈佛大学历史上最年轻的终身教授。现为哈佛大学经济学教授，曾在普林斯顿大学和麻省理工学院学习经济学；当教员时，讲授过宏观经济学、微观经济学、统计学和经济学原理。还曾做过帆船运动教练。现在与妻子和三个孩子住在麻省的威尔斯利。

曼昆是一位高产学者和一位学术与争论的经常参与者。他的著作发表在许多学术杂志上，例如：《美国经济评论》、《政治经济学杂志》和《经济学季刊》，以及更普及的报刊上，例如：《纽约时报》、《金融时报》、《华尔街日报》和《财富》。他也是最畅销的经济学教科书《宏观经济学》的作者。

Nicholas Gregory Mankiw (/ˈmæn.kjuː/; born February 3, 1958) is an American macroeconomist and the Robert M. Beren Professor of Economics at Harvard University. Mankiw is best known in academia for his work on New Keynesian economics.

Mankiw has written widely on economics and economic policy. As of March 2016, the RePEc overall ranking based on academic publications, citations, and related metrics put him as the 24th most influential economist in the world, out of nearly 50,000 registered authors. He was the 11th most cited economist and the 10th most productive research economist as measured by the h-index. In addition, Mankiw is the author of several best-selling textbooks, writes a popular blog, and since 2007 has written a column, approximately monthly, for the Sunday business section of The New York Times.