No CGI was used for the full body paint on Rob Riggle to blend in with the hotel hallway. It took six hours to paint him and blend in accurately with the vending machine.

The Farrelly Brothers couldn't get in touch with Brady Bluhm to reprise his role as Billy. They eventually found him through Facebook and were able to get him for the sequel. Due to regulations, Bluhm had to audition for the Farrellys.

Jim Carrey nearly dropped out of the sequel because he felt that the project's original producers, Warner Bros., weren't enthusiastic about the film. Carrey eventually decided to rejoin the project, although Warner Bros. dropped the project, which was then taken up by Red Granite Pictures and Universal Studios.

Numerous posters and official pieces of artwork depict Harry and Lloyd in the "dog van" from the original Dumb and Dumber. However, in the actual movie, they are in it for less than one minute of screen time.

This marks the first film since Ace Ventura: When Nature Calls (1995) where Jim Carrey reprises his character from a previous film.

Jeff Daniels won his first Emmy award the night before production began on Dumb and Dumber To.

Many of the KEN conference attendees are played by writers of the television series, Family Guy (1999).

Harry tells Lloyd, (listing his sacrifices over his achievements in their lifetime friendship) that he's watched every episode of Full House (1989). This was a real life jab at actor Jeff Daniels, as fans have often mistaken him for series star Dave Coulier.

Jennifer Lawrence filmed a cameo as Fraida in a flashback but she later requested the cameo be pulled.

In the film, Captain Lippencott is depicted as being in the special forces. In reality, Rob Riggle is a former Marine who served in Kosovo and Afghanistan.

The character name Fraida Felcher is based on the act of 'felching', a crude sexual act.

During one of the first shots of the film, when the camera pans across a room of psychiatric patients, a man on the left can be seen spelling "HELP ME" with puzzle pieces.

Jennifer Lawrence is actually a fan of Dumb and Dumber, and was rumored to originally be cast as the long-lost daughter for whom they go searching.

This is the third film that Jim Carrey has starred in for The Farrelly Brothers. The others were the original Dumb and Dumber (1994), and Me, Myself & Irene (2000).

Jim Carrey (Lloyd Christmas), Jeff Daniels (Harry Dunne), Brady Bluhm (Billy), Cam Neely (Sea Bass) and 'Sean Gildea' (unnamed friend of Sea Bass) are the only actors to reprise their roles from Dumb and Dumber (1994).

This movie has nothing to do with the 2003 movie 'Dumb and Dumberer'. In this movie Harry's parents are Asian but in 'Dumb and Dumberer' they are not.

The giant blue termite that Harry and Lloyd drive by is the exact same one they drive by in the first Dumb and Dumber.

Before Harry and Lloyd get their van back, there is a marquee sign that says "Hershey Squirts", a.k.a. diarrhea.

This film is not the first time Kathleen Turner and Jim Carrey have co-starred in a film. They first appeared together in Francis Ford Coppola's Peggy Sue Got Married (1986).

The film reunites Jim Carrey and Laurie Holden who co-starred in the film "The Majestic". Holden played Carrey's love interest in the film. In both films, Holden's character's name is Adele.

Harry (Jeff Daniels) refers to Adele (Laurie Holden) as "sugar tits" in one scene. In the first season of The Walking Dead (2010), Merle (Michael Rooker) calls her the same name.

When Billy enters his room with his parrot, the bird says "The horror, the horror", a reference to Joseph Conrad's novella Heart of Darkness, which was adapted to the screen in Francis Ford Coppola's film Apocalypse Now (1979).

Two songs featured in the film were written and sung by Jim Carrey's daughter, Jane Carrey.

Stephen Hawking was offered the role of the wheel chaired scientist in the science conference.

Comedian, Podcast host Chris Hardwick, and friend of the director Peter Farrelly, was invited to do a cameo, but due to a misunderstanding between Chris and the crew, it didn't happen, as Chris thought the invitation was for a friendly visit to the set.

Karen Duffy declined to reprise her role as Shay from the first film. Eventually she was replaced with Laurie Holden as the new female villain, Adele.

The directors wanted Laurie Holden to join the cast because of how much they hated her character in The Walking Dead (2010).

During the beginning seconds of the scene when Lloyd and Harry enter Barbara Hershey's small Kansas hometown, you can see a glimpse of the old mill wall and archways used during a scene in The Walking Dead ("Clear," Season 3, Episode 12) when Morgan disposes of the walker bodies. The mill wall is located in Grantville, GA on Church Street. What makes this trivia fact even more interesting is the actor who played Adele Pinchelow (Laurie Holden) also played Andrea on The Walking Dead for several seasons.

Channing Tatum and Emma Stone were rumored for roles at one point.

The "To" in the title actually means two in Danish and Norwegian. Therefore, the misspelling is not as "dumb" as it supposed to be.

There are three running gags in the film. 1) Someone getting pushed into some bushes, 2) Lloyd mimicking James Bond, and 3) Captain Lippencott camouflaged in the background.

The guy in a wheelchair during the fantasy scene, also appears in another Jim Carrey movie, Me, Myself and Irene (2000), as part of the police force.

In the scene where Lloyd is trying to get a signal while talking to Penny just before the camera pans to him in the top of the tree. You can see in the background on the rightside is the Cobb Performing Arts Center which was used at the end of episode 5 and through episode 6 season 1 of The Walking Dead.

Harry mentions that he's seen every episode of Full House (1987). Bob Saget, who starred in Full House, was also in Dumb and Dumberer: When Harry met Lloyd (2003).

Dumb and Dumber (1994) bears a striking resemblance with the beginning of the Gene Wilder and Richard Pryor film Stir Crazy (1980). Both films involve two friends who, after getting fired from service jobs the same day, decide to move West after an inspirational speech by one of the friends. Both films also include a road trip segment in a van, a run in with hillbilly locals and an energetic exclamation of how much they love being somewhere else. Dumb and Dumber To (2014) has some scenes in common with another Wilder and Pryor film, See No Evil, Hear No Evil (1989), where two friends are being hunted and nearly killed several times over a seemingly innocent item. There's also a sequence in both films of the friends passing as scientists/doctors to gain access to a conference/hotel with one of the friends making a very awkward appearance in the conference.

When Lloyd and Harry find their Mutt Cutz van it is implied they are in Nebraska as Lloyd recalls when he sold the van in the previous film and Lloyd and Harry were stranded in Nebraska in the previous film due to being out of gas.

The disabled man that Harry and Lloyd unintentionally make fun of is similar to Stephen Hawking a famous scientist who has Lou Gerhig's disease.

The limo driven by Harry and Lloyd was a, 1972 Cadillac Funeral Coach.

Despite, that fact that Lloyd has a shallow idea of women when Harry tells him that he'll set him up with someone his age and responds by saying "My age? Gross!". But in the 2003 film "Dumb and Dumberer: When Harry Met Lloyd", he claims that Harry's biological mother was "hitting on him" when she kissed him. Yet she would have been much older than Lloyd.

Jim Carrey wore New Balance 574 shoes in at least one scene in the film.

Rob Riggle and Patricia French previously starred together in Let's Be Cops (2014).

In this film Harry has a new pet in this case a cat named Butthole. In the original film Harry had another pet a parakeet called Petie.

The Farrelly Brothers' previous movie, The Three Stooges (2012), also featured an old rich man's trophy wife and her lover conspiring to kill him.

Bill Murray: as Icepick, Harry's new roommate.

There's a brief scene after the credits which involves Seabass and his friend, both from the original Dumb and Dumber.

After the credits the military man is also seen again camouflaged in the 'ad' for Dumb and Dumber For.

The two ambulance drivers bringing Jeff Daniels on a stretcher, after getting shot near the end of the film, are the two brothers who own Firehouse Subs, who happen to be former firefighters.

Despite the title, Lloyd actually shows some signs of intelligence. Lloyd tells Penny that Leprechauns are indeed legendary creatures based in Ireland, while Penny thought it was India. Despite being in the mental institution for twenty years, Lloyd can easily use a mobile phone, which did not exist back in 1994. Lloyd also correctly guessed that Travis was going to shoot him, and Harry to steal the box given to them by Dr. Pinchelow even though he was sarcastic. Harry, to an extent, showed a bit of intelligence, as he is seen in a running gag changing Lloyd's diapers, despite never having babies himself.

When Harry and Lloyd first arrive at the Ken Conference, Harry says "Wow, look at all the brains!". Lloyd responds with "They're blinding me with science." It's a reference to Thomas Dolby's 1982 song "She Blinded Me with Science".