In 1954 Baltimore, Wade "Cry-Baby" Walker leads a gang of "drapes", which includes his sister Pepper, a teenage mother; facially-disfigured Mona "Hatchet Face" Malnorowski; Wanda Woodward, whose post-World War II normal parents constantly embarrass her; and Milton Hackett, Hatchet Face's devoted boyfriend. Walker's ability to shed a single tear excites all the girls. One day after school, Allison Vernon-Williams, a beautiful girl tired of being a "square", approaches him, and the two fall in love. That same day, Cry-Baby interrupts a talent show at the charm school run by Allison's grandmother, and introduces himself to her, who doubts his motives. Cry-Baby invites Allison to a party at Turkey Point, a local hangout spot for the drapes.
Despite her grandmother's skepticism, Allison accompanies Cry-Baby to Turkey Point, where she is given a "drape" makeover by Hatchet Face, Pepper and Wanda, and sings a duet onstage with Cry-Baby. Later, Cry-Baby tells Allison that his father was sent to the electric chair for being the "Alphabet Bomber" – a killer who bombed places in alphabetical order ― along with his mother as an accomplice. Allison tells him that her parents took separate flights for safety, but both planes went down, orphaning her. While they are talking, Allison's jealous square boyfriend, Baldwin, ignites a riot. Cry-Baby is wrongfully blamed for the fight and sent to a penitentiary, outraging all his friends and even Allison's grandmother, who is impressed by Cry-Baby's clear love for Allison.
When Lenora Frigid, a girl with an unrequited crush on Cry-Baby, claims to be pregnant with his child, Allison feels betrayed and returns to Baldwin and the squares, though her grandmother warns her against rushing into a decision. Meanwhile, in the penitentiary, Cry-Baby gets a teardrop tattoo from fellow drape Dupree (Robert Tyree), telling him, "I've been hurt all my life, but real tears wash away. This one's for Allison, and I want it to last forever!"
Eventually, after performing with Baldwin and the Whiffles at a new theme park, Allison is persuaded by the newly established alliance between the Drapes and her grandmother to stand by Cry-Baby and join the campaign for his release. She goes to sing in front of the jail with the other drapes. Their performance persuades the judge to release Cry-Baby. Baldwin immediately insults him, revealing that his grandfather electrocuted Cry-Baby's father and that every Christmas, his family laughs at the retelling of the story. Cry-Baby challenges him to a chicken race. Cry-Baby wins, as Baldwin chickens out, and is reunited with Allison. During the race, Pepper gives birth to a baby in the backseat, and her boyfriend proposes by holding up a sign.
The film ends with all watching the chicken race crying a single tear, except for Allison and Cry-Baby, who has finally let go of the past, enabling him to cry from both eyes.
Johnny Depp as Wade "Cry-Baby" Walker
James Intveld as Cry-Baby's singing voice
Amy Locane as Allison Vernon-Williams
Rachel Sweet as Allison's singing voice
Polly Bergen as Mrs. Vernon-Williams
Ricki Lake as Pepper Walker
Traci Lords as Wanda Woodward
Kim McGuire as Mona "Hatchet-Face" Malnorowski
Darren E. Burrows as Milton Hackett
Susan Tyrrell as Ramona Rickettes
Iggy Pop as Belvedere Rickettes
Kim Webb as Lenora Frigid
Stephen Mailer as Baldwin
Alan J. Wendl as Joe "Toe-Joe" Jackson
Jonathan Benya as "Snare-Drum"
Jessica Raskin as Susie "Susie Q"
Troy Donahue as Mr. Malnorowski
Mink Stole as Mrs. Malnorowski
Joe Dallesandro as Mr. Hackett
Joey Heatherton as Mrs. Hackett
David Nelson as Hector Woodward
Patricia Hearst as Maggie Woodward
Robert Tyree as Dupree
Robert Walsh as Judge
Willem Dafoe as Hateful Corrections Officer
Kelly Goldberg as Pepper's Baby
Robert Marbury as Angelic Boyfriend