The Beagle Boys are Disney Comics characters. A family of criminals, they are usually seen trying to steal Scrooge's money.
In the comics, the individual Beagle Boys are referred to by their prison numbers, indicated on the tags seen on the chests of their distinctive orange shirts. According to one of Don Rosa's stories, the Beagle Boys have been known by their prison numbers since their childhood, and they don't even know their real names themselves. Their prison ID tags usually contained only the three digits, one, six, and seven in various combinations. The three most common numbers are 176-167, 176-671, and 176-761. Carl Barks used to include the words "Beagle Boys Inc" on their shirts under their numbers, but this was later discontinued. In later years, they appeared in the comics as a trio (some combination of the most common numbers with 671-176, 716-617 and 176-176), plus cousins and other relatives of various talents. They live in a small tumbledown hide-out in Duckburg; in 1980s American-produced stories, their pet cat Ratty often lived there as well. In the Italian stories, they are sometimes accompanied by their pet dachshund, 64, who shares their criminal mindset, but it is often overcome with 64's constant, voracious appetite.
The Beagle Boys have almost identical personalities. 176-167 in particular is very fond of prunes.
According to Don Rosa's Life and Times of Scrooge McDuck, Scrooge McDuck first met The Beagle Boys in his Mississippi riverboat days. Those Beagle Boys included Blackheart Beagle and his three sons. Scrooge first met the modern Beagle Boys during Christmas 1947, which was when he first met his grandnephews Huey, Dewey and Louie and met his nephew Donald for the second time. Since then the Beagle Boys have been a constant threat to Scrooge's huge money bin.
Sometimes they team up with other villains such as Magica De Spell, Black Pete, Mad Madam Mim, or hire out their services to Flintheart Glomgold, Ollie Eiderduck or John D. Rockerduck. During these occasions, it should be noted, they continue to operate out of their own interests rather than their employers.
In the comics, the Beagle Boys are led by their grandfather, Blackheart Beagle (number 186-802). The Blackheart character originates from two characters created by Carl Barks: Blackheart Beagle, a riverboat pirate from "The Fantastic River Race" and Grandpa Beagle, who appeared in "The Money Bin". Don Rosa later combined the character into one in chapters 10 and 11 of The Life and Times of Scrooge McDuck. Many other authors use a character purely based on The Money Bin version as the Beagle Boys' grandfather. In particular, Italian authors use a "Grandpa Beagle" who differs from Blackheart in being much skinnier and constantly smoking a pipe.
Although the characters are obviously based on dogs, they in no way resemble the actual beagle breed.
On DuckTales, the Beagle Boys were given names and different personalities. The usual character combination is Bigtime, Burger, and Bouncer, and sometimes Baggy, or Babyface, Bugle, and Bankjob. Other known names are Bomber and Blitzkrieg. Their leader is usually Bigtime, Bankjob, or their mother, Ma Beagle. In other words, the letter B is the first initial of all Beagle Boys' handles except Megabyte, the brains of the bunch.