Architect Peter Mitchell (Tom Selleck), cartoonist Michael Kellam (Steve Guttenberg), and actor Jack Holden (Ted Danson) are happy living their lives as bachelors in their lofty New York City apartment where they have frequent parties and flings with different women. Their lives are disrupted when a baby named Mary arrives on their doorstep one day. A note with her, written by a lady named Sylvia, indicates that she is Jack's, the result of a tryst between the actor and actress when they were both in a Shakespeare in the Park production of The Taming of the Shrew a year prior. Mary arrives in his absence – he is in Turkey shooting a B movie, leaving Peter and Michael to fend for themselves in taking care of her. Prior to leaving, Jack had made arrangements with a director friend to have a "package" delivered to the apartment as a favor. Before Mary's arrival, he calls and leaves a message with Peter and Michael informing them of it and to keep it a secret per the director friend's wishes. When she arrives, they mistakenly believe she is "the package", even though there is a note from her mother.
Peter and Michael are totally befuddled on how to care for Mary, and Peter leaves to go buy whatever supplies are needed. While he is gone, Mrs. Hathaway (Cynthia Harris), the landlady, delivers a small box (which is the actual "package" containing heroin) to the apartment and Michael tosses it aside while trying to keep Mary under control. After Peter returns, they eventually figure out her proper care, right down to diaper changes, baths, and feedings.
The next day, two men (who are drug dealers) arrive at the apartment to pick up the package. Peter and Michael mistakenly give Mary to them instead, and shortly after they leave, Peter discovers the actual package. He runs downstairs to intercept them, but trips and stumbles, and the package's contents spill. He gathers it and retrieves Mary from them, but retains the heroin while allowing them to take a can of powdered milk. After the exchange, a police officer attempts to ticket them for illegal parking, but they escape. He accosts Peter and detains him in the apartment until Sgt. Melkowitz (Philip Bosco), a narcotics officer, arrives to question him and Michael about the drugs. They successfully hide them from him during the interrogation, in which they learn that Jack's friend is a drug dealer as well. Melkowitz leaves with suspicions and puts them and the apartment under surveillance.
Peter and Michael are able to persuade Mrs. Hathaway to babysit Mary while they work. Once they get home, however, they find her bound and gagged and the apartment ransacked, apparently by the dealers demanding the heroin. Mary is safe, however. They continue with their care of her, adjusting to surrogate fatherhood and growing attached to her, until Jack returns.
Once Jack returns, Peter and Michael question him about the entire drug deal and Mary. He replies that he knew nothing about the heroin and initially denies everything about Mary until he reads the note from Sylvia. He then recalls the tryst that eventually led to her being born. Peter and Michael do not hesitate in taking their revenge and passing all responsibility of looking after Mary to Jack, but he quickly grows to love her.
Later, Peter discovers in the mail a news clipping of Jack's director friend being hospitalized after a mugging (presumably by the drug dealers), with a handwritten note, "Don't let this happen to you." They formulate a plan to meet and trap them when they negotiate a deal to deliver the illicit goods. With a recording of the conversation, they prove their innocence to Melkowitz and the dealers are arrested.
By now, they have fully embraced their role as Mary's guardians. However, one morning, Sylvia (Nancy Travis) arrives, asking for her back intending to take her to London to live with her family. Handing her over, they quickly find themselves miserable and desperately missing her. Deciding to stop her and Sylvia from leaving, they rush to the airport to try and persuade the latter to stay, but they arrive just as her plane is backing up from the gate. Defeated, they return home, where they find both Mary and Sylvia, who did not go to London after all. Sylvia tearfully explains she doesn't want to give up her acting career but can't do so if she has to raise Mary alone, so Peter quickly invites her and Mary to move in with them with Jack and Michael's agreement, and she agrees.
Mary was played by twins Lisa and Michelle Blair.
The soundtrack included the Peter Cetera song "Daddy's Girl", which was used for the movie's big music montage sequence, and the Miami Sound Machine song "Bad Boy", which opened it.
Just over an hour into the final cut of the film, there is a scene that shows Jack and his mother (played by Celeste Holm) walking through the house with Mary. As they do so, they pass a background window on the left-hand side of the screen, and a black outline that appears to resemble a rifle pointed downward can be seen behind the curtains. As they walk back past the window 40 seconds later, a human figure can be seen in that window. A persistent urban legend began circulating August 1990 (shortly before the sequel, Three Men and a Little Lady, premiered) that this was the ghost of a boy who had been killed in the house where the film (or this scene) was filmed. The most common version of this rumor was that a nine-year-old boy committed suicide with a shotgun there, explaining why it was vacant: because the grieving family left. This notion was discussed on the first episode of TV Land: Myths and Legends in January 2007 and was referenced in "Hollywood Babylon", a second-season episode of the TV series Supernatural.
The figure is actually a cardboard cutout "standee" of Jack, wearing a tuxedo and top hat, that was left on the set. It was created as part of the storyline, in which he, an actor, appears in a dog food commercial, but this portion was cut from the final version of the film. The standee does show up later in the film, however, when Jack stands next to it as Sylvia comes to reclaim Mary. Snopes.com contends that the one in the first scene looks smaller from its appearance in the later scene because of the distance and angle of the shot, and because the curtains obscure its outstretched arms. As for the contention that a boy died in the house, all the indoor scenes were shot on a Toronto sound stage, and no kind of residential dwellings were used for interior filming.
The critical response to Three Men and a Baby was generally positive. The film holds a 74% "fresh" rating on the movie review aggregator Rotten Tomatoes, based on 34 reviews. The site's consensus reads: "The American remake of the popular French comedy mostly works a charm under the combined talents of the three leads, who play nicely against type -- although forced plot elements and sentimentality at times dampen the fun." The film critic Roger Ebert, despite noting several aspects he saw as flaws, praised the film, remarking, "Because of Selleck and his co-stars... the movie becomes a heartwarming entertainment". He gave it 3 (out of four) stars.
The film grossed USD$170 million. It was notable for the Walt Disney Studios since it was the first production from the studio to gross over $100 million domestically. It was the highest-grossing film of 1987 domestically, with an estimated 42 million tickets sold in the US.
The film was followed by a 1990 sequel, Three Men and a Little Lady. In June 2010 it was announced that Disney was interested in filming a third film, tentatively titled Three Men and a Bride. As of 2013, the film was still listed as being in development.
This film was remade as Thoovalsparsham (1990) in Malayalam, as Chinnari Muddula Papa (1990) in Telugu, as Asathal (2001) in Tamil and Heyy Babyy (2007) in Hindi.
Early TV comedy sketch parodies of Three Men and a Baby included a famous sketch on In Living Color where Muhammed Ali, Mike Tyson and Sugar Ray Leonard are played by David Alan Grier, Keenen Ivory Wayans and Tommy Davidson.
In the 2009 film The Hangover, where three of the main characters acquire a missing baby while searching for their lost friend, character Alan Garner references the film, saying, "It's got Ted Danson, Magnum, P.I., and that Jewish actor".
In the TV show Home Improvement, season 4 episode 21, Tim manages to change a tire in 38 seconds. The head racer says, "In that amount of time, we could change 23 tires and a baby", to which Al Borland replies, "I love that movie.", referencing the film. Earl Hindman (Wilson) played the minor role of Satch, Vince's assistant, in the film.