The short scene during the party where Ace pulls the cellist's arm as he walks by, making him produce a false tone, was improvised by Jim Carrey.

The voice of Ace Ventura and the manner in which he speaks was added by Jim Carrey only after several read throughs of the script. The voice was something Carrey used in his stand up routine. The "All righty then" was the catch phrase of one of his stand up characters and after the lines from the script weren't feeling right, he added it to the script and read through it again using that voice for all the lines. It was such an improvement that it became the main Ace Ventura personality trait.

The giant hook Ace used to knock out two of Einhorn's henchmen was originally supposed to knock their heads off, the filmmakers decided to quickly cut away so they'd survive instead.

Ace Ventura compares Ray Finkle's room to Hannibal Lecter's prison cell from The Silence of the Lambs (1991). Seventeen years later, in Inside the Actors Studio: Jim Carrey (2011), Jim Carrey recounted that he asked Anthony Hopkins to dinner and discovered that his approach to Ace Ventura was the same as Hopkins' to Hannibal Lecter: they moved like animals. Carrey based Ventura's movement on birds and Hopkins based Lecter's movements on reptiles. Carrey confessed that Hopkins was becoming Hannibal Lecter right at the table.

The entire scene where Ace Ventura claims to be expert dolphin trainer Heinz Getwellvet was originally cut out of the theatrical release. It was added back in when the movie was released on videotape in June 1994, and was advertised as "additional footage not seen in theaters".

The original concept is the Pet Detective character was a bumbling idiot, until Jim Carrey was cast and his character was rewritten.

Originally Ace wasn't written to be animal-related, but more of a generic Sherlock Holmes parody. Screenwriter Jack Bernstein came up with the pet detective idea after watching a David Letterman sketch about pet owners.

In a 2011 interview, Tom Shadyac admitted that when he first saw the film, he was worried that it might end his and Jim Carrey's careers.

The ass-talking scene started in In Living Color (1990). Frustrated one day with Keenen Ivory Wayans' constant rejection of his pitched sketches, Jim Carrey stood up and read a sketch from his butt, in Wayans's direction. The two almost fought before Wayans walked out of the room. "Later, we sat down, talked, and everything was cool," Wayans said.

According to Tom Shadyac in the DVD commentary, Jim Carrey came up with "Alrighty then" and other lines specifically because he thought they might catch on. The hand gesture Ventura gave before leaving the police station was also something Carrey intended to become popular. It did not.

Ace Ventura's landlord is named Mr. Shickadance. When Jim Carrey was growing up in Toronto, he lived in an apartment building that was managed by Schikedanz Brothers.

Rick Moranis turned down the role of Ace Ventura.

Jennifer Aniston told a story about visiting Courteney Cox and bringing a copy of this film to watch. Courteney refused to watch it.

Jim Carrey revealed on Inside the Actors Studio (1994) that he based Ace Ventura on a smart bird. "A cockatiel or a parakeet of some kind. The clothing I picked was all ... like a colourful bird, a tropical bird. The walk was bird-like. Everything was about a bird, when I spoke ... Everything was based on a bird, even the hairstyle."

Jim Carrey had his own personal chef on the set of the film, who also was required to prepare meals for Carrey's pet iguana.

Jim Carrey uses the same voice and mannerisms for his In Living Color (1990) sketch character, Overly Confident Gay Man, as he did for Ace Ventura. In one of the sketches, he even uses the "Alrighty Then" phrase.

The ficticious shipping company in the opening scene is called "hds" when each individual letter is flipped 180 degrees, it reads "ups", the company clearly parodied in this scene.

Woodstock's nickname for Ace Ventura is "St. Francis". This is in reference to St. Francis of Assisi, the Catholic patron saint of animals. Later in the movie, when Ace is at Shady Acres, a statue of St. Francis of Assisi can be seen behind the doctor as he is talking to Courtney Cox's character.

Lauren Holly turned down the role played here by Courteney Cox but co-starred with Jim Carrey in Dumb and Dumber (1994) later in the year.

The real final score of Super Bowl XIX (1985) was San Francisco 38, Miami 16. The game footage of 'Ray Finkle' used in the film is actually a 1984 clip of Dolphins kicker Uwe von Schamann.

"Shady Acres Mental Hospital" is named for director Tom Shadyac.

The screenplay is credited to Jack Bernstein, Tom Shadyac, and Jim Carrey, but writer Steve Oedekerk (who would later write and direct Ace Ventura: When Nature Calls (1995)) and Carrey would work on jokes for Pet Detective from midnight until 4 a.m. after working "15- or 16-hour" days on In Living Color (1990). Oedekerk described himself and Carrey as "two giddy idiots tossing jokes around."

In the scene after the landlord examines the apartment, we see penguins emerge from a pet door in the refrigerator. The single black line of feathers in the white field of their torso indicates these are tropical penguins who don't live in cold temperatures. They are very frequently used in productions to stand in for cold weather penguins from the frigid South Pole because the easier logistics involved with no needing to provide a cold environment for the birds and because most people don't know the difference.

Tom Shadyac's directorial debut.

After Ace knocks out the henchman he briefly does his Fire Marshall Bill laugh.

Ace's car is a 1972 Chevrolet Monte Carlo.

In the movie, the Dolphins play the Super Bowl at Joe Robbie Stadium, their home field. In reality (as of the 2019 NFL season), no NFL team has played a Super Bowl in its home stadium, although NFL rules do not prohibit teams from playing a Super Bowl in their own stadium.

Cannibal Corpse made their guest appearance in this movie. The song that they were playing was "Hammer Smashed Face", one of their most famous songs.

A note found in Lt. Einhorn's desk is dated January 17, which is also Jim Carrey's birthday.

The tabloid magazine in Ace's apartment is called the "National Intruder."

Carrie-Anne Moss and Téa Leoni were considered for the role of Melissa Robinson.

Jim Carrey's breakout role.

Judd Nelson and Alan Rickman were considered for the lead role.

Alice Drummond (Mrs. Finkle) and David Margulies (the doctor at Shady Acres Mental Hospital) previously appeared in Ghostbusters (1984), with Margulies reprising his role for "Ghostbusters 2" (1989). They both passed away in 2016.

At the police station, Ace tells Einhorn, "I've come to confess. I was the second gunman on the grassy knoll." This was probably a joke about James Files, a convicted felon who in 1994 came forward as one of JFK's assassins. His claims have since been debunked.

At one point, this was conceived as a vehicle for Rob Schneider. But Schneider turned it down.

Morgan Creek believed that the film would be "Fletch (1985) for the 90s".

The Super Bowl as shown at the end of the film is between the Miami Dolphins and Philadelphia Eagles.

The plot of Ray Finkle missing the game winning field goal in the Super Bowl is loosely based on Buffalo Bills kicker Scott Norwood in Super Bowl XXV, which occurred three years prior to the film's release. However in 2016, 22 years after the film's release in a case of life imitating art, Minnesota Vikings kicker Blair Walsh missed a game winning field goal in a playoff game against the Seattle Seahawks in the "Laces Out" manner similar to Finkle.

While Melissa talks with the doctor at the Shady Acres Mental Hospital (1:00:18), immediately behind her is a statue of St. Francis of Assisi. St Francis is the patron saint of animals.

The band playing in the club is Cannibal Corpse, an American death metal band from Buffalo, New York.

The "Hi, Captain Stubing, how are Gopher and Doc?" comment that Ace makes toward Ronald Camp's butler is a reference to The Love Boat (1977).

At one point, the producers considered making Ace female, being named Alice instead, and with Whoopi Goldberg as their preferred choice.

Included among the American Film Institute's 2000 list of the 500 movies nominated for the Top 100 Funniest American Movies.

Ace wears Ray-Ban "Balorama" sunglasses.

Courteney Cox's character, Melissa Robinson, was named after original writer Jack Bernstein's daughter Melissa.

During the apartment investigation, right after Lieutenant Einhorn fakes out Ace with a handshake, Ace says "Oh there is just one more thing, Lieutenant" This is a common phrase spoken by another fictional detective, minus the "Lieutenant". Lieutenant Columbo would often say "Just one more thing" in order to pester his suspects into slipping up.

Ace's line "Man, I'm tired of being right!" is quite similar to a quote by Ian Malcolm (Jeff Goldblum) in Jurassic Park (1993): "Boy, do I hate being right all the time!" Jim Carrey was once in the running for that part, and appeared with Goldblum in Earth Girls Are Easy (1988).

John Capodice's character, Sgt. Aguado, named after producer Ken Aguado.

In the Snowflake tank scene, Ace impersonates Captain Kirk, Dr. McCoy and Scotty from Star Trek (1966).

During the scene when Ace is trying to figure out the connection between Einhorn and Finkle a picture of Batman and Robin can be seen on his mantle. Jim Carrey would go on to play the Riddler in Batman Forever.

As of 2020, no NFL team has played in a Super Bowl game at their home stadium.

The exterior shot of Ron Camp's mansion is that of Vizcaya Museum in Key Biscayne, Florida.

In the scene where Melissa is talking to a psychiatrist about Ace, they are standing beside a statue of St. Francis of Assisi, the patron saint of animals. Also, Ace is called "St. Francis" earlier by his activist friend at the head banger club.

The movie contains several Batman connections. Jim Carrey played Edward Nygma/The Riddler in Batman Forever (1995). Sean Young was originally cast for the Vicki Vale role in Batman (1989) that went to Kim Basinger and attempted to land the Selina Kyle/Catwoman role in Batman Returns (1992) that went to Michelle Pfeiffer. Bill Zuckert, who plays Ray Finkle's father in this movie, appeared in the penultimate episode of Batman (1966). Courtney Cox dated Michael Keaton, one of the actors who played Batman.

Adam Sandler turned down the role of Ace Ventura.

When Ace Ventura first sneaks past Mr. Shickadance watching television in his apartment, a scene from Stay Tuned (1992) shown on the screen.

The film has several connections to Nicolas Cage. Jim Carrey worked with Cage in "Peggy Sue Got Married" (1986). Randall 'Tex' Cobb worked with Cage in "Raising Arizona" (1987). Noble Willingham had an uncredited role in "Guarding Tess" (1994). Courteney Cox was briefly Cage's sister-in-law when she was married to David Arquette and Cage was married to Patricia Arquette.

For the Castilian Spanish language dub version, Jim Carrey's voice was dubbed by José Luis Gil.

Tom Shadyac: Detective at the police station.

The actor playing Ray Finkle in the photo of the Dolphin's group shot is actually Sean Young in a wig and fake mustache.

According to Courteney Cox, while filming her sex scene with Jim Carrey, all the animals in Ace's apartment had to be chained down. "But the squirrel would get loose and jump on the penguin. The penguin would bite the cockatoo and soon all hell would break loose and I'd find myself under the blanket with a macaw."

When Ace is first informing Lt. Einhorn about his Ray Finkle theory, on the desk there are two apples and a banana positioned in a suggestive manner. This foreshadows the fact that Lt. Einhorn is actually the male Finkle.

Jim Carrey came up with the idea of ripping off Sean Young's clothes to reveal her in her bra and underwear in the end.

The Crying Game (1992) parody wasn't in the screenplay, as it was not released until production on Ace Ventura was already under way. Using the music and the idea for parodying it was a last-minute decision.

Einhorn is German for Unicorn, a mythological animal with a phallic appearance.

There was supposed to be a scene after Ace crashed his car while chasing Dan Marino's kidnappers. The white pigeon landed on his car, he got it singing "I got the white pi-geon! I got the white pi-geon". Then, in a parody of The Birds (1963), he is surrounded by birds that started tearing him apart. Then he wakes up with a big "whew." It was removed from the finished film since it was too dark.

When Ace Ventura first meets Lt. Einhorn, he looks down toward her crotch and exclaims: "Holy Testicle Tuesday." This is foreshadowing that Einhorn's true gender is male.

In the scene when Ace is proving the scream came from inside Roger Podacter's apartment, he picks up Roger's dog. Shortly after Einhorn walks up to them and the dog barks at Einhorn. This is likely foreshadowing that she was previously at the apartment and the one who killed Podacter.

The film was heavily criticised by the LBGT community for being homophobic and transphobic in its handling of a transgender villain and Ace's reaction to kissing her. Tom Shadyac defended this joke after some anti-defamation groups got on his case about it, saying that it was less about making fun of transpeople and more about how easily Ace will break from simply kissing another man despite all of his endeavors.

15 minutes into the movie when Ace is watching the training video of Snowflake to get familiar with the case he noticed that Snowflakes call number is "Blue 42" latter when Ace is pretending to be insane he uses the same call sign "Blue 42".

When Ace reveals to the cops at the end that Einhorn is actually Ray Finkle, all the cops get sick and throw up cause they were actually kissing a man, behind Aquado a female cop is also shown getting sick, showing she was a lesbian actually kissing a man pretending to be a woman.

When Ace is informing Lt. Einhorn about his Ray Finkle theory she lunges at him and start kissing to which Ace says "Your gun is digging into my hip", which is of course not a gun and hints at Lt. Einhorn's real identity

Although the Super Bowl is featured at the end of the film it is never stated who wins.

There are two clues as to what is really going on as far as the real suspect in Podacter's "suicide" murder. First is when Ace inspects the dog for clues and the dog reacts aggressively toward Einhorn when she walks up to Ace. This is the first major hint that Einhorn is not who she appears to be. Second is when Ace sarcastically mentions animals being able to sense evil. Einhorn thinks this is a clue that Ace might know the truth so she follows him to the balcony to mock his findings, but this is actually to find out what he knows. This is the second hint in this scene that Einhorn isn't who she appears to be.

When Lt. Einhorn enters and Ace first addresses her he exclaims "Holy Testicle Tuesday!" which foreshadows future events.