Production notes

After the popularity of the Muppets had grown following the success of The Muppet Show, Lew Grade agreed to finance the production of the film and signed the deal with his company ITC Entertainment, which helped Jim Henson finance the film. After the film's production greenlit, Jim Henson and selected team members traveled to California various times to develop the script, music, and infrastructure in Hollywood to shoot the film. James Frawley was hired to direct the movie due to the film's challenges. During Frawley and Henson's first meeting in London, they were concerned that the Muppets would not blend well in real life. Along with Frank Oz and the team, they filmed and tested how the characters would appear in real-world locations during the first few days of June 1978 in a UK meadow. During filming tests, a cow was ambled near Fozzie for an unexpected rear look at a comparison between fake and natural fur hair. The camera tests attracted the investment of ITC Entertainment. On July 3, 1978, Henson flew to Los Angeles again to begin shooting for the film.

Principal photography began on July 5, 1978, and continued for 87 days during summer and fall of that year. Each minute took a day to be filmed. Filming locations included Albuquerque, New Mexico as well as various parts of Los Angeles and Northern California, including the San Fernando Valley. The Western street scenes were filmed on the former Columbia Ranch, then known as The Burbank Studios. Additionally, the interior shots were filmed at CBS-MTM Studios. All the sets were elevated by five feet to allow the puppeteers to perform. According to Henson, the principal photography of the film was slower than in television. No effects were added after filming concluded. Austin Pendleton recalled that the film was shot on "a very unhappy set, because Jim [Frawley] was very unhappy directing that movie. And I noticed that was the only time the Muppet people used an outside person to direct a Muppet movie. They never did that again. After that, it was either Jim Henson or Frank Oz. And I would have liked to have been in one of those, because those sets were very harmonious. But this was not." Several shots required Muppets standing and acting in a full-body shot. To perform Kermit sitting on a log, Henson squeezed into a specially designed metal container complete with an air hose (to breathe), a rubber sleeve which came out of the top to perform Kermit and a monitor to see his performance, and placed himself under the water, log, and the Kermit puppet. He was also assisted in this operation by Kathryn Mullen and Steve Whitmire. During breaks, cups of ice tea were given to Henson through the rubber sleeve since he could not easily leave the tank. Rescuers had to stand by the tank to pull Henson out if the tank leaked or the air supply had difficulties. The scene took five days to be filmed. In order for Kermit to ride a bicycle in a full-body shot, a Kermit puppet with legs was posed onto the seat and his legs and arms were attached to the pedals and handlebars. An overhead crane with a marionette system held the bicycle through strong strings invisible to the camera, guiding the bicycle forward. The crane and system were out of the camera's frame of vision. Specially made, remote-controlled puppets were placed on the set and controlled by puppeteers out of the frame. A dancing Kermit and Fozzie Bear were operated by Henson and Oz in front of a blue screen, and they were composited onto a separate reel of the stage. For scenes involving Fozzie driving a Studebaker, cables, TV monitors, puppeteers, and its Muppets were filled in. A dwarf would sit in the trunk and control via remote control. A television monitor showed what was ahead. The closing reprise of "Rainbow Connection" featured a crowd of more than 250 Muppet characters—virtually every Muppet that had been created up to that point in time. According to Henson Archivist Karen Falk, 137 puppeteers were enlisted from the Puppeteers of America (along with the regular Muppets performers) to perform every Muppet extant. Prior to the day-long filming of the shot, Henson gave the enthusiastic participants a lesson in the art of cinematic puppetry. The scene involved 150 puppeteers performing in a pit that was 6 feet (1.8 m) deep and 17 feet (5.2 m) wide. In September 1978, Edgar Bergen, Henson's idol who appeared in a cameo role, died shortly after completing his scenes. Henson was asked by his family to say a few words with Kermit for his memorial service. Henson agreed, and he attended Bergen's memorial service for its speech. Henson dedicated the film to his memory.

The film's music and lyrics were written by Paul Williams and Kenneth Ascher. Regarding the music's composition, Williams said; "Jim Henson gave you more [creative] freedom than anybody I've ever worked with in my life. I said, 'You want to hear the songs as we're writing them?' He said, 'No. I'll hear them in the studio. I know I'm gonna love them.' You just don't get that kind of freedom on a project these days." "Never Before, Never Again" was originally sung by Johnny Mathis, but was changed to Miss Piggy when Jim Henson thought it would be funnier if she sang it to herself. Mathis would later sing the song in the television special The Muppets Go Hollywood. "Movin' Right Along", "Never Before, Never Again", and "I Hope That Somethin' Better Comes Along" were shortened in the film, compared to their soundtrack versions, for continuity purposes. The latter, a duet between Rowlf and Kermit, contained references that the studio considered too mature for children, although the song appeared complete in the British theatrical and home video debut versions.

In its first six days at the Leicester Square Theatre, it grossed $31,884. The film would later earn over $76.7 million in the United States and Canada, returning $32 million in box office rentals. For 32 years, The Muppet Movie was the highest-grossing puppet film until the release of The Muppets in 2011. The film's successful theatrical release encouraged Lew Grade into furthering his own film distribution company, which later backfired with the massive box office failures of Can't Stop the Music (from EMI) and Raise the Titanic (from ITC), both released by Associated Film Distribution just a year later.

The Muppet Movie currently holds an 89% approval rating on Rotten Tomatoes, based on 102 reviews. The site's consensus says "The Muppet Movie, the big-screen debut of Jim Henson's plush creations, is smart, lighthearted, and fun for all ages." On Metacritic, the film has a weighted average score of 74 out of 100 based on 7 reviews, indicating "generally favorable reviews". The film received highly positive reviews in the United States. Roger Ebert of the Chicago Sun-Times gave the film three-and-a-half out of four stars. In his favorable review, he was fascinated that "The Muppet Movie not only stars the Muppets but, for the first time, shows us their feet." Vincent Canby of The New York Times offered equal praise, stating that the film "demonstrates once again that there's always room in movies for unbridled amiability when it is governed by intelligence and wit." Gene Siskel of the Chicago Tribune gave the film three-and-a-half stars out of four and called it "surely one of the summer's most entertaining films," which "does a fairly nice job of trying to be all things to all people. Which is not an easy job." Dale Pollock of Variety wrote, "'The Muppet Movie' is a winner... Script by Jerry Juhl and Jack Burns incorporates the zingy one-liners and bad puns that have become the teleseries' trade mark, but also develops the Muppets themselves as thinking, feeling characters." Kathleen Carroll of the New York Daily News wrote that "with the exception of Brooks' wacky scene and Steve Martin's funny bit as a snooty waiter, the cameo appearances by such stars as Bob Hope and Richard Pryor tend to slow the action down just as the bland musical numbers by Paul Williams and Kenny Asher interrupt the flow of the movie. Still The Muppet Movie should entrance both young and old as the Muppets further endear themselves with their crazy antics, their playful puns and their very human characteristics." Rex Reed, in the same newspaper, reacted more enthusiastically to the film, remarking that "if there's any doubt, The Muppet Movie will make believers and fans out of the worst pessimists. These lovable characters are so real and so endearing that I was never aware of the human hands making them work from mysterious hiding places. The Muppets made a wide-eyed, child out of me, and I hope they continue to do so until I'm in my wheelchair." Charles Champlin of the Los Angeles Times wrote, "as you might well expect, it is hip, funny, technically ingenious, fast-moving, melodious, richly produced, contemporary and equally and utterly beguiling to grown-ups and small persons." Katrine Ames of Newsweek stated, "'The Muppet Movie' is a delectable grab bag of influences — stories by L. Frank Baum and Lewis Carroll, Westerns, the Crosby-Hope and Garland-Rooney movies — as well as its own inventive devices. The result is a kind of 'That's Entertainment!' with a plot attached. Its charm — and success — lie primarily in its loving pokes at Hollywood conventions and in the lovable characters who do the poking." John Skow of Time magazine offered a more mixed response, saying that "the transition from the yank-'em-off-if-they-bomb lunacy of the TV show to the coherent narration of the film is not a complete success. Muppet magic remains a bewildering succession of wonderful bits, and perhaps the movie's best occurs when Rowlf the Dog, who is a barroom pianist, commiserates with Kermit, who has just been deserted by Miss Piggy. The two sing a nice, rueful song about women—the can't-live-with-them, can't-live-without-them kind of thing." Michael Hanton of the Toronto Star wrote that "I was looking forward to a combination of Singin' in the Rain, Citizen Kane, and Intolerance. What I got was more like Gidget, The Great Race and Love Boat"; he also remarked that Fozzie Bear stole the show from his favorite character, Miss Piggy.

In the United Kingdom, it received mixed to positive reviews. Tim Radford of The Guardian called it "another film spun slightly longer than it should have been", adding that "the humour remains decently dry and self-deprecating throughout; on the other hand there isn't nearly enough of it, and a good 40 or 50 minute idea is padded to the obligatory hour and a half with songs, travelogue, flashbacks and a certain amount of mooning about." Patrick Gibbs of The Daily Telegraph remarked that "after the Wombles moved, as they did recently, from the small screen to the big, so the Muppets inevitably follow, rather more successfully, I think, for James Frawley’s The Muppet Movie is a clever construction." He also said that "the style is cunningly varied at intervals by the appearance in virtually two-line parts of such people as Milton Berle, James Coburn, Dom DeLuise or Elliott Gould, not to mention Orson Welles, each in his own comic persona. Songs also help to add variety to a very hazardous undertaking; not at all to my taste, it comes off, I would say, as well as possible." Alexander Walker of the London Evening Standard supplied the film with its most positive review in the country, calling it "the most original little show in town", and adding that it offered:Across the board delight: not only for the children: for adults, too, who'll relish its in-jokes, visual wit, cheeky parodies of other movies and [its] own brand of surrealist fun. That's the first surprise. The second is how successfully the Muppets take to the big blow-up of the cinema screen. But this is no jumped-up clone of the TV show. It expands its own fun to fill its enlarged running-time. It reminds you of a "Road" film. But instead of Hope, Crosby and Lamour, it has a cloth-and-styrofoam cast who look more human than the famous humanoids like Orson Welles, Mel Brooks, Telly Savalas and (yes) Bob Hope they meet en route.

The Muppets "magic," supplied by creator-producer Jim Henson and other talented artists operating the globe puppets from hiding places that a sewer rat would think cramped, endow their stars with independent life and liveliness.

In 2009, it was selected for preservation in the National Film Registry by the Library of Congress for being "culturally, historically or aesthetically significant." In 2020, "Rainbow Connection" was deemed "culturally, historically, or aesthetically significant" by the Library of Congress and selected for preservation in the National Recording Registry. One of the two 1951 Studebaker Commander 2-door sedans used in the film is now on display at the Studebaker National Museum in South Bend, Indiana. The car was used for the driving scenes. The bottom of the front seat was removed, and the puppeteers lay on the floor to move the muppets. The car was driven by an operator seated in the trunk using remote controls. A camera hidden in the "bullet" at the front of the car provided a closed-circuit video feed to a monitor in the trunk for the operator. In July 2025 the car completed an 18-month restoration.