- Acting for Two: Jemaine Clement as both 2012 Boris and 1969 Boris.
- Billing Displacement: Although Tommy Lee Jones gets second billing, he's only on screen for 15 minutes.
- Dawson Casting:
- K is supposed to be 29 in 1969. He's played by Josh Brolin, who was 43 during the filming. J lampshades this, looking incredulously at K and snarking "Got some city miles on ya, huh?"
- Inverted with Will Smith as Smith was born in 1968. We learn J was at least 4-5 in 1969, making J a few years older than Will Smith.
- Also inverted with O. Emma Thompson was born in 1959 and thus would have been ten in 1969. The younger version of O looks to be in her mid to late twenties and is played by Alice Eve who would have been 28 to 29 during filming.
- Fake Brit: In the third film, Boris the Animal is played by the New Zealand actor Jemaine Clement. He's technically an alien, but he speaks with a British accent reminiscent of Tim Curry.
- McLeaned: Combined with Role-Ending Misdemeanor. Zed was killed off because Rip Torn had been arrested for drunk driving. And broke into a bank with a loaded firearm. So, more like Role Ending Felony.
- Separated-at-Birth Casting: Josh Brolin is a remarkably good young Tommy Lee Jones.
- Sequel Gap: It was released ten years after Men in Black II.
- Throw It In!: The Funny Background Event by one of the guards when J, K and Griffin are talking to the colonel.
- What Could Have Been:
- Production delays forced Alec Baldwin to drop out of the film. Alec was the original choice to play Chief X, the head of the Men In Black agency in the sixties.
- Sacha Baron Cohen was considered for the role of Boris The Animal.
- Gemma Arterton was originally cast as young Agent O, but scheduling conflicts prevented Arterton from taking the role.
- Michael Bay expressed interest in directing.
- Writing by the Seat of Your Pants: Filming began without a completed script, which led to a delay in production, so the screenplay could be rewritten and completed.
Trivia / Men in Black 3