Robert McDowell Parker Jr. (born July 23, 1947) is a retired American wine critic. His wine ratings on a 100-point scale and his newsletter The Wine Advocate are influential in American wine buying and are therefore a major factor in setting the prices for newly released Bordeaux wines. This made him the most widely known and influential wine critic in the world.

Parker was born in Baltimore, Maryland. His father was a construction equipment salesman. He has an honors graduate of the University of Maryland, College Park, with a major in history and a minor in art history. He continued his education at University of Maryland School of Law at the urban campus of the University of Maryland, Baltimore, graduating in 1973 with a Juris Doctor degree. He discovered wine as a student visiting Alsace, where Patricia, now his wife, was studying. For over ten years, he was assistant general counsel for the Farm Credit Banks of Baltimore; he resigned in March 1984 to focus on writing about wine.

In 1975, Parker began writing a wine guidebook. Taking his cue from consumer advocate Ralph Nader, Parker wanted to write about wine without the conflicts of interest that might taint the opinions of other critics who also make a living selling wine. In 1978, he published a direct-mail newsletter called The Baltimore-Washington Wine Advocate, which was later renamed The Wine Advocate. The first issue was sent free to consumers from mailing lists Parker purchased from several major wine retailers. Six hundred charter subscribers paid to receive the second issue published later that year.

Parker received worldwide attention when he called the 1982 vintage in Bordeaux superb, contrary to the opinions of many other critics, such as San Francisco critic Robert Finigan, who felt it was too low-acid and ripe. While there is still debate about the timelessness of the vintage, prices of 1982 Bordeaux remain consistently higher than other vintages.

More than twenty years later, The Wine Advocate has over 50,000 subscribers, primarily in the United States, but with significant readership in over 37 other countries. While other wine publications have more subscribers, The Wine Advocate is still considered to exert a significant influence on wine consumers' buying habits, particularly in America. New York Times wine critic Frank Prial asserted that "Robert M. Parker Jr. is the most influential wine critic in the world."

A lengthy profile of Parker entitled "The Million Dollar Nose" ran in The Atlantic Monthly in December 2000. Among other claims, Parker told the author that he tastes 10,000 wines a year and "remembers every wine he has tasted over the past thirty-two years and, within a few points, every score he has given as well." Yet, in a public blind tasting of fifteen top wines from Bordeaux 2005—which he has called "the greatest vintage of my lifetime"—Parker could not correctly identify any of the wines, confusing left bank wines for right several times. (In general, "left bank" wines are grown in regions west of the Gironde Estuary, and "right bank" in the regions east.)

In addition to writing and tasting for The Wine Advocate, which is published six times a year in Monkton, Maryland, Parker has been a contributing editor for Food and Wine Magazine and BusinessWeek. He has also written periodically for the British magazine The Field and has been the wine critic for France's L'Express magazine, the first time a non-Frenchman has held this position.

Among the books and films that have focused on the influence and effects of Parker on the global wine industry are the 2004 book The Accidental Connoisseur, by Lawrence Osborne, the 2004 documentary film Mondovino by Jonathan Nossiter, a 2005 unauthorized biography The Emperor of Wine by Elin McCoy, the 2008 book The Battle for Wine and Love: Or How I Saved the World from Parkerization by Alice Feiring, and the 2010 French language bande dessinée comic book, Robert Parker: Les Sept Pêchés capiteux.