Mysterious, otherworldly visitors who are believed intimidate witnesses of UFO activity into keeping quiet. MIBs, who dress entirely in black, were very prevalent in the 1950s and early 1960s. Also believed to be automatons.

Men in Black is a 1997 science fiction comedy action film directed by Barry Sonnenfeld, starring Tommy Lee Jones, Will Smith and Vincent D'Onofrio. The film was based on the comic book series The Men in Black by Lowell Cunningham, by Aircel Comics which is owned by Marvel Comics. The film featured the creature animation of Rick Baker.

The song "Men in Black" was recorded by rapper and actor Will Smith (also featuring singer Coko) for the movie Men in Black, in which he also starred. The song plays during the movie's closing credits. Will Smith raps about how the MiBs "Walk in shadow, move in silence" and play the role of "first, last and only line of defence, against the worst scum of the universe."

The comic book The Men in Black was created and written by Lowell Cunningham, illustrated by Sandy Carruthers, and published by Aircel Comics. Aircel would later be bought out by Malibu Comics, which itself was bought out by Marvel Comics. Three issues were published in 1990, with another three the following year.

In The X-Files television show, The Men in Black (MIB for short, and singular, Man in Black) refer, unofficially, to a group of enforcers employed by the Syndicate to take care of the dirty work of the conspiracy (i.e., murders, intimidation, sabotage, cover-ups, etc). Most of them were ex-military, highly trained, loyal, cold-blooded, mafia-style hitmen, who worked, as a front, in government agencies such as the FBI, DOD, and NSA. Some, mostly shown in comedic episodes, parodied the traditional view of MIBs from UFO lore.

Men in Black (1934) is the third Three Stooges short film in the Columbia Pictures series. It features the Stooges playing hapless med school graduates on their first day on the job at a hospital.