Bette Davis had a Coca-Cola machine installed on set. This was to deliberately provoke Joan Crawford, who was married to the chairman of Pepsi.

According to Bette Davis in her book "This N' That," the film was originally going to be shot in color. Davis opposed this, saying that it would just make a sad story look pretty.

The wig Bette Davis wears throughout the film had, unbeknownst to both leads, been worn by Joan Crawford in an earlier MGM movie. Because it had been re-groomed, Crawford didn't recognize it.

In scenes where Jane imitates Blanche's voice, the voice heard is actually Joan Crawford's voice, and not Bette Davis', as Davis could not master Crawford's voice properly.

This film was a smash hit upon initial release, recouping its original budget in only 11 days, and eventually grossing $9 million. In adjusted 2017 dollars, this would be equivalent to $72,596,920.53.

Bette Davis was nominated for the Oscar for Best Actress for her performance in this movie. Had Davis won, it would have set a record number of wins for one actress. According to the book "Bette & Joan - The Divine Feud" by Shaun Considine, Davis and Joan Crawford had a lifelong mutual hatred, and a jealous Crawford actively campaigned against Davis winning Best Actress, even telling Anne Bancroft that if Bancroft won and was unable to accept the Award, she would be happy to accept it on her behalf. According to the book, on Oscar night Davis was standing in the wings of the theater waiting to hear the name of the winner. When it was announced that Bancroft had indeed won for The Miracle Worker (1962), Joan marched past Davis with barely an "excuse me" and swept onstage to accept Bancroft's Oscar.

In her book "This N' That," Bette Davis said she had a lot of control over how her makeup should be done for the film. She imagined the older Jane as someone who would never wash her face, just put on another layer of makeup. When her daughter, Barbara Merrill, first saw her in full "Jane" makeup, she said, "Oh, mother, this time you've gone too far."

Bette Davis and Joan Crawford worked hard to promote the film, both knowing that their profit percentage points would pay off in spades with the film's success. Davis traveled to 17 theaters across the state of New York in three days for personal appearances and helped give away promotional "Baby Jane" dolls to patrons with a "lucky envelope" under his or her seat.

Early on, Bette Davis made the decision to create her own makeup for Jane. "What I had in mind no professional makeup man would have dared to put on me," said Davis. "One told me he was afraid that if he did what I wanted, he might never work again. Jane looked like many women one sees on Hollywood Boulevard. In fact author Henry Farrell patterned the character of Jane after these women. One would presume by the way they looked that they once were actresses, and were now unemployed. I felt Jane never washed her face, just added another layer of makeup each day." Davis' garish makeup made her look something akin to a grotesque version of an aging Mary Pickford gone to seed, and she loved it. She took pride when Farrell visited the set one day and exclaimed, "My God, you look just exactly as I pictured Baby Jane." The outrageousness of Davis' appearance caused some concern for Aldrich and the producers, who feared it might be too over-the-top. However, as time went on, they came to see that Davis' instincts for the character were right.

While touring the talk show circuit to promote the movie, Bette Davis told one interviewer that when she and Joan Crawford were first suggested for the leads in this film, Warner Bros. studio head Jack L. Warner replied: "I wouldn't give a plugged nickel for either one of those two old broads." Recalling the story, Davis laughed at her own expense. The following day, she reportedly received a telegram from Crawford: "In future, please do not refer to me as an old broad!"

The budget was so limited that the production wasn't able to use the usual process screen shots for Jane's driving scenes. Bette Davis did her own driving around Hollywood with cameraman Ernest Haller perched either in the back seat of the car or over the front fender in order to get the shots he needed. "To this day," said Davis in 1987, "I smile when I remember the first time 'Jane' drove down Beverly Boulevard in an old Hudson. The expressions on the faces of people in other cars when they saw me were hysterical. Lots of mouths dropped."

During the filming of Hush...Hush, Sweet Charlotte (1964), Joan Crawford acknowledged to visiting reporter/author Lawrence J. Quirk the difficulty she was having with Bette Davis because of the Oscar incident but added, "She acted like Baby Jane was a one-woman show after they nominated her. What was I supposed to do, let her hog all the glory, act like I hadn't even been in the movie? She got the nomination. I didn't begrudge her that, but it would have been nice if she'd been a little gracious in interviews and given me a little credit. I would have done it for her."

Joan Crawford was an avid collector of Margaret Keane's "sad eyes" paintings and befriended the couple and tried to incorporate their work into her films. In the film, during the interior scenes of the neighbor's (Mrs. Bates) house, several Keane paintings can be seen displayed on the walls.

While Bette Davis took delight in looking dreadful for the film, the opposite was true of Joan Crawford. Even though Blanche had once been a beautiful young actress, she was now in her 50s, confined to a wheelchair, emaciated and wasting away. It was difficult for Crawford to appear unattractive, since she had always been considered one of Hollywood's most glamorous stars. "It was a constant battle to get her not to look gorgeous," said Davis. "She wanted her hair well dressed, her gowns beautiful and her fingernails with red nail polish. For the part of an invalid who had been cooped up in a room for 20 years, she wanted to look attractive. She was wrong."

Exterior shots of the Hudson house were filmed at 172 S. McCadden Pl. in Los Angeles. Right next door at 180 S. McCadden Pl. is the house Judy Garland lived in during production of Võlur Oz (1939).

Because she was then a member of the Pepsi-Cola board of directors, Joan Crawford managed to see that product placement shots of the soft drinks appeared in all of her later films. Although nearly imperceptible, Pepsi does show up in this one. During the last sequence, a guy runs up to the refreshment stand on the beach and tries to collect the deposit on some empty Pepsi bottles--a transaction that actually only happened in stores.

According to Bette Davis, Robert Aldrich convinced Joan Crawford to let go of some of her glamorous embellishments. "It took him one entire morning to talk her into removing her nail polish for a scene in which she came downstairs with her hand on the railing," said Davis.

Bette Davis found doing the scene in which the adult Jane sings her maudlin childhood signature song, "I've Written a Letter to Daddy," particularly memorable. "The old Jane gazing in the mirror from about 12 feet away looks pretty good," described Davis. "Then she walks forward. Ernie [cameraman Ernest Haller] had a high light, straight down, which is always bad for a woman. Especially me. When Jane finally gets up to the mirror, she sees herself as this decrepit old hag, when in her mind she's still young. I covered my face with my hands. [Robert Aldrich] had wanted a loud scream, but what came out was a hoarse cry--I'd been having laryngitis. It was right and we both knew it. [Aldrich] had tears in his eyes. 'You just won yourself an Oscar,' he whispered. I went home that night singing, 'And the Angels Sing'."

Despite her criticisms, Bette Davis did have some praise for Joan Crawford every now and then. She called Crawford a "pro" who was always on time and always knew her lines perfectly. She also saw some similarities between herself and Crawford. " . . . I suppose we have the same drive," she told writer Whitney Stine. "She's a survivor and so am I. And I suppose I do infuriate people the same way she does." Davis felt that Crawford's behavior was reasonably under control--"because, I suppose, she wanted to be as professional as I was," said Davis.

This film is considered by many as Joan Crawford's last important picture. After this film, she was relegated to several lower-budgeted horror films until her last picture, Trog (1970), in 1970 and some TV appearances in 1971 and 1972.

When production began, both Bette Davis and Joan Crawford were excited about the project. The budget was shoestring and the schedule was tight, but they were thrilled to go to work every day and trusted that Robert Aldrich would make a wonderful movie.

When producer William Frye considered taking an option on the novel in 1960, he and friend Bette Davis tried to get Alfred Hitchcock interested in directing. He declined, as he was busy promoting Psycho (1960) and trying to develop The Birds (1963) into a screenplay.

When Joan Crawford started sending little gifts and notes to the crew to win their affection, Bette Davis sent her a note telling her to "GET OFF THE CRAP".

It takes a while for both leads to appear on screen, with Joan Crawford appearing first while watching her character's old picture. Bette Davis finally appears about a minute later, and by this point, it's nearly 20 minutes into the picture.

The cracked head of the Baby Jane doll featured prominently in the film's ad campaign was a completely different doll than that actually used in the movie, probably because the film was shot and released so quickly that the ad staff had to devise the campaign while the film was still in production.

Peter Lawford was originally set to play the part of Edwin Flagg, but two days after accepting the part he withdrew due to family concerns. Lawford felt the character might reflect badly on his real-life role as brother-in-law of the current President, John F. Kennedy. Victor Buono was then cast as Edwin. Bette Davis originally objected to Buono's casting but eventually came around.

Joan Crawford was scheduled to appear alongside Bette Davis on a publicity tour for the film but canceled at the last minute. Davis claimed that Crawford backed out because she didn't want to share the stage with her. In a 1972 telephone conversation, Crawford related to author Shaun Considine that after seeing a screening of the film she urged Davis (who wasn't interested) to go and have a look. When Joan didn't hear back from her co-star, she called Davis and asked her what she thought of the film, to which Bette replied, "You were so right, Joan. The picture is good. And I was terrific." Crawford: "That was it. She never said anything about my performance. Not a word." Considine alleges that this denial from Davis (with regards to Joan's talent as an actress) prompted Crawford to cancel the publicity tour and upstage Davis at the Oscars.

Many critics consider this movie as the creation of the "hag horror" subgenre.

The principal shooting was completed in roughly a month. "[Aldrich] really cut the picture in the camera," said Bette Davis. "He had to, because we didn't have time for many setups, and he wanted to show the picture for a week in the Los Angeles area to qualify for Academy consideration." Robert Aldrich told the "New York Times". "We finished shooting on schedule on September 12. Exactly one month later we held our first sneak preview, at the State Theatre in Long Beach, California. That we were able to get the picture in shape in this incredibly short time is due to a group of dedicated craftsmen who performed above and beyond the call of duty--and almost beyond physical endurance--who worked virtually around the clock to meet our schedule."

Ingrid Bergman, Susan Hayward, Rita Hayworth, Katharine Hepburn, Jennifer Jones and Ginger Rogers were considered for Baby Jane.

In the preamble to the film, there is a clip from Bette Davis' older film, Ex-Lady (1933), used as an early film for Jane Hudson. Bette climbs from her bed to look out her window. On the table beside her bed is a framed photo of her beau, played by Gene Raymond, who is also arriving in the car on the street below. Later on Blanche is watching her own old film Sadie McKee (1934). The man she visits in the hospital in her older movie clip and the man she leaves Edward Arnold for is Gene Raymond.

Baby Jane picks up her altered costumes from "Western Costumes" which is, in reality, one of the largest costume houses in Hollywood.

The role of Liza Bates (teenage daughter of the next-door neighbor, Mrs. Bates) was played by Barbara Merrill (credited as B.D. Merrill), daughter of Bette Davis by her third husband, Grant Sperry. B.D. was adopted by Davis' fourth husband, Gary Merrill, at the age of three, but dropped the last name at age 16, going by B.D. Sherry until her marriage in 1963 to Jeremy Hyman.

Features Victor Buono's only Oscar-nominated performance.

In addition to her trademark number "I've Written a Letter to Daddy", the young Baby Jane apparently had other hit songs in her act. When Edwin prepares to play the piano for their rehearsal, we see Jane's picture featured on old sheet music for songs entitled "Fly the Flag of Freedom", "She's Somebody's Little Girl", and "I Wouldn't Trade My Daddy".

The film takes place in 1917, 1935 and 1962.

The film is included on Roger Ebert's "Great Movies" list.

Tallulah Bankhead, Claudette Colbert, Olivia de Havilland and Marlene Dietrich were considered to play Blanche.

Although many people believed the film would be a flop, even on a budget of notably less than $750,000, it took just 11 days to go into profit and was one of 1962's biggest box-office hits.

Included among the "1001 Movies You Must See Before You Die", edited by Steven Schneider.

Bill Walker appeared in a deleted scene delivering a package to Jane at the Hudson Mansion. It was filmed in the studio recreation of the house but never made it to the final release. He is uncredited.

Included among the American Film Institute's 1998 list of the 400 movies nominated for the Top 100 Greatest American Movies.

Margaret Keane (I)'s "Big Eyes" painting "The Stray" is hanging beside the entrance at Mrs. Bates' house.

In What Ever Happened to Baby Jane? (1962), the Hudson sisters' business manager is named Bert Hanley; Bert Hanley is also the name of the fading Broadway songwriter who wrote the fictional one-hit wonder show "Children's Crusade" in the 2003 film Camp (2003), an obvious nod to "....Baby Jane."

Barbara Merrill: The curious teenager who lives next door to the Hudson sisters is Bette Davis' real-life daughter.

A freeze-frame just as the car enters the driveway in the prologue reveals the secret of who was driving the car the night Blanche was paralyzed.

According to Bette Davis, Joan Crawford refused to dispose of her falsies: "As part of her wardrobe, Miss Crawford owned three sizes of bosoms. In the famous scene in which she lay on the beach, Joan wore the largest ones. Let's face it, when a woman lies on her back, I don't care how well endowed she is, her bosoms do not stand straight up. And Blanche had supposedly wasted away for 20 years. The scene called for me to fall on top of her. I had the breath almost knocked out of me. It was like falling on two footballs!"

The house exterior of the Hudson mansion is located at 172 South McCadden Place in the Hancock Park section of Los Angeles. Other residential exteriors show cottages on DeLongpre Ave. near Harvard Ave. in Hollywood without their current gated courtyards. The scene on the beach was shot in Malibu, reportedly the same site where Robert Aldrich filmed the final scene of Kiss Me Deadly (1955).