Robber Baron is a pejorative term used for a powerful 19th century businessman. By the 1890s, the term was typically applied to businessmen who were viewed as having used questionable practices to amass their wealth. It combines the sense of criminal ("robber") and illegitimate aristocracy ("baron"). U.S. political and economic commentator Matthew Josephson popularized the term during the Great Depression in a 1934 book by the same title.

List of businessmen who were called robber barons

• Philip Danforth Armour Sr.
• John Jacob Astor, real estate, fur
• John Jacob Astor III, fur trader and real estate investor
• George Fisher Baker
• Charles T. Barney
• August Aaron Belmont, Sr.
• John Insley Blair
• Wellington R. Burt
• Adolphus "Prince" Busch Sr., (USA)
• Samuel Prescott Bush, industrialist
• Andrew Carnegie, railway entrepreneur and steel manufacturer
• William Andrews Clark Sr., U.S. Senator/Montana & Copper Magnate, copper
• Jay Cooke, railroad executive
• Charles Crocker, railroad executive
• Daniel Drew, railroad executive
• James Buchanan Duke, energy and tobacco industry executive
• Eleuthère Irénée du Pont, Founder and Managing Partner of DuPont, chemicals, industrialist
• George Eastman
• James G. Fair, U.S. Senator
• James Clair Flood
• William Fargo
• Marshall Field, retail
• "Diamond Jim" Fisk, steel manufacturer
• Henry Flagler, oil industrialist and railroad executive
• Henry Ford, automobiles
• Henry Clay Frick, steel manufacturer
• John Warne Gates, financier, barbed wire promoter and oil industrialist
• Stephen Girard, financier
• Jay Gould, railroad executive
• E. H. Harriman, railroad executive
• George Hearst, U.S. Senator, mining, newspapers
• William Randolph Hearst
• Frederick Augustus Heinze, copper
• James Jerome Hill
• Charles T Hinde, railroads, water transport, shipping, hotels
• Mark Hopkins, Jr., railroad executive
• Collis Potter Huntington, railroad executive
• Theodore Dehone Judah
• John William Mackay
• Cyrus Hall McCormick
• Andrew W. Mellon, banker and politician
• Richard B. Mellon
• William Henry Moore
• J. P. Morgan, banker, financier, and railway entrepreneur
• Charles Wyman Morse
• William Shoney O'Brien
• John Cleveland Osgood, coal mining, iron
• Lewis Cass Payseur, railroad executive
• Henry B. Plant, railroad executive
• Charles William Post
• Joseph Pulitzer
• George Mortimer Pullman
• Patroon General Stephen Van Rensselaer, III
• John D. Rockefeller, oil industrialist and railway entrepreneur
• William Avery Rockefeller, Jr.
• Henry Huttleston Rogers
• Russell Sage
• Jacob Schiff, financier
• Charles M. Schwab, steel manufacturer
• Richard Warren Sears
• Joseph Seligman, banker, financier, and railway entrepreneur
• Isaac Merritt Singer
• Samuel Slater
• Claus Spreckels (Spreckels Sugar Company)
• John D. Spreckels, sugar manufacturer, railway entrepreneur, and real estate investor
• Leland Stanford, railroad executive and politician
• Alexander Turney Stewart, dry goods
• James Stillman
• Moses Taylor
• Charles Lewis Tiffany
• Cornelius Vanderbilt, shipping entrepreneur and railroad executive
• William Henry Vanderbilt
• Henry Villard
• William Weightman
• Henry William Dwight Wells
• Friedrich Weyerhaeuser, timber mogul
• Cassius Milton Wicker
• Frank Winfield Woolworth
• Charles Yerkes, railway entrepreneur