David Cay Boyle Johnston (born December 24, 1948) is an American investigative journalist and author, a specialist in economics and tax issues, and winner of the 2001 Pulitzer Prize for Beat Reporting.

From 2009 to 2016 he was a Distinguished Visiting Lecturer who taught the tax, property, and regulatory law of the ancient world at Syracuse University College of Law and the Whitman School of Management. From July 2011 until September 2012 he was a columnist for Reuters, writing, and producing video commentaries, on worldwide issues of tax, accounting, economics, public finance and business. Johnston is the board president of Investigative Reporters and Editors. He has also written for Al Jazeera English and America in recent years.