In the Good Old Summertime is a 1949 American Technicolor musical romantic comedy film directed by Robert Z. Leonard. It stars Judy Garland, Van Johnson, S. Z. Sakall, Spring Byington, Clinton Sundberg, and Buster Keaton in his first featured film role at MGM since 1933.

The film is a musical adaptation of the 1940 film The Shop Around the Corner, which was directed by Ernst Lubitsch, starring James Stewart, Margaret Sullavan, and Frank Morgan, and written by Miklós László, based on his 1937 play Parfumerie. For In the Good Old Summertime, the locale has been changed from 1930s Budapest to turn-of-the-century Chicago, but the plot remains the same. The plot was also revived in the 1998 film You've Got Mail, starring Tom Hanks and Meg Ryan.

On a spring day in Chicago, in the early 1900s, Andrew Larkin is the top salesman at Otto Oberkugen's music store. On his way to work, he runs into Veronica Fisher. When Andrew arrives, he rushes to the post office and reads a letter from his secret pen pal, known as "Box Number 237." That same day, Veronica arrives at the store requesting a job there. Mr. Oberkugen initially refuses to hire Veronica, but he hires her after she persuades a customer to buy a harp. Several months pass and the store's sales dwindle, in which Veronica and Andrew's professional relationship turns contentious. Regardless, their pen pal relationship turns romantic.

During the wintertime, Andrew and Veronica, unbeknownst to each other, arrange to have dinner together. However, Oberkugen has the staff to stay overtime to take a store inventory, upsetting both Andrew and Veronica. Their coworker Nellie Burke manages to have Oberkurgen change his mind after she confesses her love towards him. Outside the restaurant, Andrew learns Veronica is his secret pen pal. Disappointed at first, he returns to the restaurant, but does not reveal to Veronica that he is her pen pal. Instead, he attempts to flirt with Veronica, but they fall into a heated argument. Andrew leaves, and Veronica returns home thinking her date failed to show. The next day, Veronica calls in sick. Andrew comes to visit Veronica and invites her to Otto and Nellie's engagement party.

Back at work, Oberkugen hands Andrew his prized Stradivarius violin to safeguard for the party. Instead, Andrew loans the violin to his friend Louise to perform at a recital. At the engagement party, Veronica performs two musical numbers, one with a barbershop quartet and a solo number. For the next number, Oberkugen asks for his violin, to which his nephew Hickey clumsily breaks. Oberkugen is distraught at first, but Andrew tells him that his real violin is with Louise. Andrew and Oberkugen arrive at Louise's recital, and Oberkugen fires him for loaning Louise his violin.

On Christmas Eve, when Andrew returns to collect his belongings, his coworkers tell him their goodbyes. Nellie arranges Oberkugen to write a letter of recommendation for Andrew. However, Oberkugen changes his mind, and promotes Andrew as the new store manager giving him a raise. He also allows for Louise to keep his violin. During the store hours, Oberkugen gives Veronica her bonus, although she intends to quit in protest to Andrew's promotion. When the store closes, Andrew reveals to Veronica that he is her secret pen pal. They kiss, and she consents to marry him.

• Judy Garland as Veronica Fisher
• Van Johnson as Andrew Delby Larkin
• S. Z. "Cuddles" Sakall as Otto Oberkugen
• Spring Byington as Nellie Burke
• Clinton Sundberg as Rudy Hansen
• Buster Keaton as Hickey
• Lillian Bronson as Addie
• Marcia Van Dyke as Louise

• "In the Good Old Summertime" (George Evans, Ren Shields)
• "Meet Me Tonight in Dreamland" (Leo Friedman, Beth Slater Whitson)
• "Put Your Arms Around Me, Honey" (Albert Von Tilzer, Junie McCree)
• "Play That Barbershop Chord" (Lewis Muir, Willam Tracey)
• "I Don't Care" (Harry Sutton, Jean Lenox)
• "Merry Christmas" (Fred Spielman, Janice Torre)

Garland introduced the Christmas song "Merry Christmas" in this film; it was later covered by Johnny Mathis, Bette Midler, and cabaret artist Connie Champagne.

Director Robert Leonard originally hired Buster Keaton as a gag-writer to help him devise a way for a violin to get broken that would be both comic and plausible. Keaton came up with an elaborate stunt that would achieve the desired result; however, Leonard realized Keaton was the only one who could execute it properly, so he cast him in the film. Keaton also devised the sequence in which Johnson inadvertently wrecks Garland's hat and coached Johnson intensively in how to perform the scene. This was the first MGM film that Keaton appeared in after having been fired from the studio in 1933.

The picture was filmed between November 1948 and January 1949.

Garland's three-year-old daughter, Liza Minnelli, makes her film debut, walking with her mother and Van Johnson in the film's closing shot.

The song "Last Night When We Were Young" was written in the 1930s by Harold Arlen and E. Y. "Yip" Harburg for the Metropolitan Opera star Lawrence Tibbett. Garland loved it and wanted to include it in the film. It was recorded and filmed but when the picture was released, it was cut from the final print. The audio recording of "Last Night When We Were Young" was featured on several of Garland's MGM record albums and she also later recorded it for Capitol Records in the 1950s. The entire footage of the number was found in the MGM vaults and included in the PBS documentary American Masters: Judy Garland: By Myself in 2004.

The film was made during the height of the strained relationship between Garland and MGM. As a testament to Garland's strong popularity, it was a huge critical and commercial success. According to MGM records, it earned $2,892,000 in the US and Canada and $642,000 overseas, resulting in a profit of $601,000.

It was the second-to-last film that Garland made at MGM (with the final being Summer Stock). MGM terminated her contract – by mutual agreement – in September 1950.

The film is recognized by American Film Institute in these lists:

• 2006: AFI's Greatest Movie Musicals – Nominated

• List of Christmas films

• In the Good Old Summertime at IMDb 
• In the Good Old Summertime at the AFI Catalog of Feature Films
• In the Good Old Summertime at the TCM Movie Database
• In the Good Old Summertime at AllMovie
• The New York Times overview
• The Judy Garland Online Discography In the Good Old Summertime pages
• The Judy Room In the Good Old Summertime filmography entry