Spaceball I lurks through space. Aboard, Sergeant Rico informs Colonel Sandurz that Planet Druidia is in sight. The fearsome Lord Dark Helmet arrives on the ship's bridge and is informed that they are approaching Druidia. Helmet proceeds to tell President Skroob, but Rico says he has already told Skroob. Angered over Rico going "over his helmet," Helmet uses his Schwartz-ring on Rico's testicles. Helmet requests to see Druidia on radar and Sandurz reveals their plan to kidnap Princess Vespa in order to retrieve the combination to the planet's air-shield from Vespa's father, King Roland.
At the First Intergalactic Temple (Reformed) of the Druids, Vespa, her father, and the droid of honor, Dot Matrix prepare for Vespa's wedding to Prince Valium. Vespa gets cold feet, stopping several times as they approach the altar. Ultimately, Vespa runs away – Dot in tow – and leaves the planet.
A Winnebago christened the Eagle 5 flies through space, occupied by Captain Lone Starr and his co-pilot, Barf. They receive a call from Pizza the Hutt, who demands the 1,000,000 Spacebucks they owe him.
Vespa and Dot leave Druidia's atmosphere. Under scrutiny by Dot, Vespa insists she is glad she ran away from the wedding.
At his office in Spaceball City, President Skroob tells a caller that there is no air shortage on Planet Spaceball. After hanging up, regarding the caller as a "shithead," Skroob inhales a can of Perri-Air from his desk. He is then contacted by Commanderette Zircon, informing him that Spaceball I has Vespa in its sights and is closing in on her. Snotty beams Skroob to the control room, but his head is backwards. He is beamed back to his office and he walks the short distance to the control room. He observes the radar screen of Vespa and Spaceball I, giving the command to capture her alive.
On the Spaceball I bridge, Helmet orders fire across the nose of Vespa's ship and she calls her father. Some of the shots hit the vehicle and Helmet reprimands the cross-eyed Gunner's Mate First Class Phillip Asshole and was assigned to the position by his cross-eyed cousin, Major Asshole. It is then revealed that most of the bridge crew is comprised of Assholes. Helmet then orders the Assholes to resume firing.
King Roland contacts Lone Starr and Barf and begrudgingly agrees to pay them 1,000,000 Spacebucks for Vespa's rescue from the Spaceballs.
As Vespa's car is pulled toward Spaceball I, Lone Starr and Barf spot them. They jam the ship's radar, prompting a Radar Technician to contact Helmet and Sandurz and they discover it to be jammed by raspberry jam. Helmet immediately blames Lone Starr.
Lone Starr pilots the Eagle 5 to Vespa's car as Barf helps transport Vespa, Dot, and Vespa's luggage into the Eagle 5. Upon seeing the princess's luggage, Lone Starr and Vespa are immediately at odds with one another, which is perturbed further by Vespa's complaints of the ship and the fact that she is a Druish princess.
Vespa's car is pulled into Spaceball I, which the Spaceballs discover to be empty. The radar is repaired and the Eagle 5 is spotted on the radar. Spaceball I approaches, but the Eagle 5's hyper jets are engaged, allowing them to escape. Dark Helmet gives the order to engage in ludicrous speed. This causes the ship to pass by the Eagle 5, prompting Barf to comment that Spaceball I has "gone to plaid." Noticing that they've passed their target, Helmet orders the ship to stop, causing him to crash into a control panel and soon faint.
Although the escape from the Spaceballs, Eagle 5 runs out of fuel and crash lands on the nearby moon of Vega. As Lone Starr and Vespa fight, Barf talks sense into them and they leave the Winnebago, hauling Vespa's luggage.
They soon stop, Lone Starr and Barf exhausted from carrying what they find to be an industrial-strength hair drier. Lone Starr attempts to talk sense into the princess and before another fight breaks out, Barf suggests they find a place to camp.
The Spaceballs search for the Eagle 5 and Sandurz suggests they check the video cassette of Spaceballs, the movie. Helmet expresses doubts, as they are in the middle of making the film, but a Corporal finds it, due to a breakthrough in home video technology where cassettes are in stores before the movie is finished. They search through the film and eventually find Vespa, Lone Starr, Barf, and Dot on the moon of Vega.
At their campfire, Lone Starr tells Vespa of his origins, that he was found on a monastery doorstep after being born somewhere in the Ford galaxy. He shows her a necklace he had had his whole life, but had never determined the meaning of it. Vespa then tells him she ran from her wedding because she did not love the groom, yet regrets her actions, knowing that love was not something a princess was guaranteed. The to prepare to kiss, but Dot's 'virgin alarm' goes off and separates the two.
The group treks across the desert, Lone Starr and Barf thirsty for water, Dot needing oil, and Vespa begging for room service. Eventually, the group collapses.
As Spaceball I approaches the moon, a group of Dinks discover Lone Starr, Barf, Dot, and Vespa and give them water and replenish their fluids before leading them across the desert.
The Spaceballs begin searching the moon as the Dinks bring the fugitives to a cave, where they meet the wise, all-powerful, and magnificent Yogurt, a keeper of the power, the Schwartz. Yogurt then shows them a plethora of Spaceballs merchandise.
Back in Spaceball City, Skroob entertains Charlene and Marlene before Zircon interrupts, telling him that Helmet has lost sight of Vespa. Skroob orders them to "comb the desert," which they literally do, but turn up nothing.
Lone Starr shows his necklace to Yogurt, who says the writing on it cannot be revealed to Lone Starr until the right time. He then teaches Lone Starr how to use the power of the Schwartz, allowing Lone Starr to lift a statue of Yogurt, smashing Barf's foot in the process.
The Spaceballs continue their search and Helmet feels the presence of the Schwartz and Sandurz discovers Yogurt's insignia. They resolve to not enter the cave, instead deciding to lure the princess out, which they do by using a hologram of her father, allowing them to capture her and Dot.
Lone Starr and Barf bid Yogurt goodbye. Yogurt gives Lone Star a fortune cookie and assures him that they will meet again in the sequel, Spaceballs 2: The Search for More Money. Yogurt also gives Lone Starr the Schwartz ring, stating that he might need it.
Helmet plays with his Spaceballs dolls, acting out a scenario where he defeats Vespa's friends and she falls in love with him until Sandurz interrupts, telling him he is needed on the bridge.
In Spaceball City, Skroob is informed by Zircon that Helmet and Sandurz have brought the princess to his office. In the office, Vespa is prepared to have a nose-job to return her original nose if King Roland does not give them the air-shield combination. As the surgery is prepared, he relents, revealing that it is 1-2-3-4-5. Skroob arrives and they tell him the combination.
Lone Starr and Barf arrive in Spaceball City and disguise themselves as Spaceballs. They enter Prison Ball 28, where Vespa and Dot are being held. They free the two and attempt to escape, leading to a shootout with Spaceball forces. They soon are able to run slip from Spaceball grasp when their stunt doubles are caught instead. As the rest open the Eagle 5, Vespa dispatches the remaining Spaceballs on their tail.
Skroob arrives on the Spaceball I bridge as they approach Druidia. They prepare the ship for metamorphosis into Mega Maid, witnessed by the crew aboard the Winnebago. With Mega Maid, the Spaceballs plan to suck all of the air from Druidia. Mega Maid begins its operation, causing King Roland to begin to suffocate. Lone Starr stops Mega Maid by using the Schwartz to reverse its vacuum cleaner, saving Roland from death.
Lone Starr pilots the Eagle 5 into Mega Maid to search for its brain. He exits the Winnebago, incapacitates a Spaceball with a Vulcan neck pinch and prepares to set Mega Maid to self-destruct. Armed with the Schwartz and a can of Spaceballs: The Shaving Cream, he defeats another Spaceball. As he prepares to press the self-destruct button, Dark Helmet enters and the two duel.
Helmet soon tricks Lone Starr into a handshake, which he uses to take his ring and drop it through a floor grate. Yogurt speaks to Lone Starr, telling him to use the Schwartz, as the ring had merely come from a Cracker Jack box. Lone Starr uses the Schwartz to grab a mirror and deflect an attack back into Helmet, causing him to stumble into the self-destruct button.
The Spaceballs scramble to abandon ship as Lone Starr returns to the Eagle 5 to make an escape. Skroob, Helmet, and Sandurz are unable to reach escape pods and Mega Maid explodes.
Lone Starr and Barf learn that Pizza the Hutt has died after eating himself to death inside his limo. They return Vespa and Dot to King Roland before taking off to a diner. There, they witness a singing alien tear its way out of a customer's stomach and decide to leave.
Vespa and her father prepare for 'take-two' of the wedding. Vespa is angered over Lone Starr leaving, but Roland informs her that he did not take his reward.
Lone Starr and Barf open the fortune cookie from Yogurt, which shows them a vision of him, informing Lone Starr that his necklace means that he is a prince. He further says he left special fuel for them in the glove compartment: Liquid Schwartz. They pour the Liquid Schwartz into the emergency gas tank and go turn around to return to Druidia.
Inside pieces of Mega Maid, Skroob, Sandurz, and Helmet crash land on the planet of the Apes.
At the wedding, Vespa asks her father why he held back the information about Lone Starr and realizes that Lone Starr loves her. Accompanied by Barf, Lone Starr arrives, announcing that he is a prince, prompting Vespa to agree to marry him instead.
The Eagle 5 flies away with 'Just Married' written on the back window as a message appears, reading 'May the Schwartz be with you.'
- Mel Brooks as President Skroob and Yogurt
- John Candy as Barf
- Rick Moranis as Dark Helmet
- Bill Pullman as Lone Starr
- Daphne Zuniga as Princess Vespa
- Dick Van Patten as King Roland
- George Wyner as Colonel Sandurz
- Michael Winslow as Radar Technician
- Joan Rivers as the Voice of Dot Matrix
- Lorene Yarnell as Dot Matrix
- John Hurt as John Hurt
- Sal Viscuso as Radio Operator
- Ronny Graham as Minister
- Jm J. Bullock as Prince Valium
- Leslie Bevis as Commanderette Zircon
- Jim Jackman as Major Asshole
- Michael Pniewski as Laser Gunner
- Sandy Helberg as Dr. Schlotkin
- Stephen Toblowsky as Captain of the Guard
- Jeff MacGregor as Snotty
- Henry Kaiser as Magnetic Beam Operator
- Denise Gallup as Charlene
- Dian Gallup as Marlene
- Gail Barle and Dey Young as Waitresses
- Rhonda Shear as Woman in Diner
- Robert Prescott as Sand Cruiser Driver
- Jack Riley as TV Newsman
- Tom Dressen as Megamaid Guard
- Rudy DeLuca as Vinnie
- Tony Griffin and Rick Ducommun as Prison Guards
- Ken Olfson as Head Usher
- Bryan O'Berne as Organist
- Wayne Wilson as Trucker in Cap
- Ira Miller as Short Order Cook
- Earl Finn as Guard with Captain
- Mitchell Bock as Video Operator
- Tommy Swerdlow as Troop Leader
- Tim Russ as Trooper
- Ed Gale, Antonio Hoyos, Felix Silla, Arturo Gil, Tony Cox, and John Kennedy Hayden as the Dinks
- Deanna Booher as Bearded Lady
- Johnny Silver as Caddy
- Brenda Strong as Nurse
- Dom DeLuise as the Voice of Pizza the Hutt
- Spaceballs was one of Mel Brooks' most expensive movies to make. It cost US$22.7 million to make.
- Spaceballs was not the first Star Wars parody. It came after Hardware Wars.
- George Lucas allowed Brooks to make Spaceballs, as long as he didn't make any merchandising. He ended up actually liking the movie.
- The novelization was written by R.L. Stine.
- The tagline on the poster says, "May the Farce be with you." Never once is this line said in the actual movie, though it may be a slight paraphrase of, "May the Schwartz be with you", which is a line said by Yogurt.