Did You Know?

While the Murtaugh family waits for the commercial, they watch Tales from the Crypt, specifically episode #1.2, Tales from the Crypt: And All Through the House (the psycho Santa episode), which aired on 10 June 1989, starring Mary Ellen Trainor, who plays police psychiatrist Dr. Stephanie Woods in this movie. Some episodes in the series were produced by the film's director, Richard Donner.

The bottle of cologne that is shot during the destruction of Riggs' trailer is "Hero." The first time we see Riggs going into his trailer, there is an ad for that same cologne on TV.

Leo's "okay-okay-okay" schtick was based on Disneyland employees giving directions to Fantasyland. Originally, Leo was going to be an oily, effeminate character, but Joe Pesci didn't want to play him that way. He pitched the idea of making Leo all-too-eager to please, complete with "okay-okay-okay" ad libs, to Richard Donner. Donner laughed and said, "Do that! Do that!"

Riggs was originally to die on the boat, but the producer decided to make more movies, hence his survival, after being shot three times.

The body count is 33, the highest of the 'Lethal Weapon' series.

Main cinematography took place in the spring of 1989.

Keith Haring's "Free South Africa" poster is seen in a few background shots as it is in Scrooged, also directed by Richard Donner.

One scene that was cut out, but restored in the DVD Director's Cut, is an extended version of Leo trying to show Riggs and Murtaugh where the "house with stilts" is located. In the scene, they are parked off road and Leo is trying to recall the address. He keeps going on and on that the address has to add up to 9 because "nine is my lucky number". Meanwhile, Riggs and Murtaugh look through a map book and randomly pick a street to go down. Following this scene is the one already in the film of them finding the house. The deleted scene further explains Leo's remark "I told you. Nine that's my lucky number," after Murtaugh moans "This is the ninth possibility, Leo."

The scene where Murtaugh does his 'Free South Africa' tirade - his statement of 'one man, one vote' did in fact, became part of then-South Africa's president F.W. de Klerk agenda to end apartheid, lift the ban on the African National Congress (in the film, protesters outside the South African Consulate had the ANC flag), and released Nelson Mandela from incarceration. Danny Glover did portray Nelson Mandela in the made-for-cable HBO film Mandela (1987), which was filmed prior to the release of the first Lethal Weapon film.

Riggs intentionally dislocates his shoulder in this film in order to get out of a straitjacket, then has to slam his shoulder back into place. This becomes a running gag throughout the series, where he slams his shoulder back into place after riding a motorcycle off a bridge in Lethal Weapon 3 and Ku (Jet Li's character) dislocates both of Rigg's shoulders in a fight scene in Lethal Weapon 4.