Gregory Peck's nine-minute summation speech was nailed in just one attempt.

Mary Badham (Scout) and Gregory Peck (Atticus) became close during filming, and kept in contact for the rest of his life. Peck always called her "Scout", her character role.

The first scene that Gregory Peck shot showed him returning home from his character's law office while his children ran to greet him. Author Harper Lee was a guest on the set that day, and Peck noticed her crying after the scene was filmed. He asked Lee why she was crying, and she responded that Peck had looked just like her late father, the model for Atticus. Lee explained that Peck even had a little round stomach like her father's. "That's not a pot belly, Harper," Peck told her, "That's great acting".

After being offered the role of Atticus Finch, Gregory Peck quickly read Harper Lee's novel in one sitting and called director Robert Mulligan immediately afterwards to say that he would gladly play it.

Brock Peters, who played Tom Robinson in the film, delivered Gregory Peck's eulogy on the date of his funeral and burial, Monday, June 16, 2003.

Brock Peters (Tom Robinson) started to cry while filming his testifying scenes, without rehearsing it this way, and Gregory Peck (Atticus Finch) said that he looked past him, instead of looking at him in the eye, to avoid choking up himself.

Official credited film debut of Robert Duvall, who had no dialogue.

The watch used in the film was a prop, but Harper Lee gave Gregory Peck her father's watch after the film was completed, because he reminded her so much of him.

Director Robert Mulligan learned quickly not to rely on numerous takes, as he found that his child cast members became less natural and spontaneous after the first several.

Robert Duvall stayed out of the sun for six weeks and dyed his hair blonde for the role of Arthur "Boo" Radley, who, according to the story, spent much of his life as a recluse. The character of Radley is based in part on Harper Lee's recollection of Alfred "Son" Bouleware, who lived with his parents in a dilapidated, mostly boarded-up house just a few doors away from the Lee house. His father kept him confined to the house after young Alfred was involved in an incident of vandalism. Described in the book and in the movie as leaving the house only at night, because the sun hurt his eyes, this might suggest that Boo Radley suffered from Albinism (lack of pigment in the skin, in the hair and in the irises of the eyes).

Atticus Finch was modeled on Harper Lee's own father, Amasa "A.C." Lee, an attorney and Alabama state legislator whose 1923 defense of a black client partially inspired the novel's trial. Like Amasa Lee, the character of Atticus Finch was not only an attorney but also a state legislator and a widowed single father. Gregory Peck met with Amasa Lee, then 82 years old, and formed a strong bond with him. Unfortunately, Lee died while the movie was filming, so Harper gave Peck his watch and chain. Peck was wearing that same watch and chain at the Academy Award ceremony the following year, when he won the Oscar for Best Actor.

Despite universal praise for the novice film actress and actor, neither Mary Badham nor Phillip Alford chose to capitalize on their stunning film debuts. Badham retired from acting and married a schoolteacher, living near Richmond, VA, and spent most of her time raising her two children. Alford later became a successful businessman in Birmingham, AL.

Atticus Finch was voted as the #1 screen hero of the last 100 years by the American Film Institute (AFI) in its special, "100 Years, 100 Movies, 100 Heroes & Villains".

It has been reported that this film was Gregory Peck's favorite work.

Phillip Alford told his mother that he did not want to go to the auditions for the part of Jem Finch, but when his mother told him he would miss half a day of school, he immediately decided to go.

According to author Neal Gabler in the biography "Triumph of the American Imagination", Walt Disney saw this film and lamented, "That's the kind of film I wish I could make." At the time Disney was creatively stymied, producing broad family comedies such as The Parent Trap (1961) and The Absent Minded Professor (1961), but he would soon find a fulfilling project in Mary Poppins (1964).

Truman Capote, who grew up with Harper Lee, also knew the inspiration for Arthur "Boo" Radley, and had planned to base a character on him in one of his short stories. After seeing how well the character was realized in Lee's novel, he decided against it.

The character of Dill was based on Truman Capote, who had been a childhood friend of Harper Lee, when he was sent to live with relatives in Lee's hometown each summer. Capote, in turn, based one of his characters in his literary work "Other Voices, Other Rooms" upon his recollection of Harper Lee. In interviews, Lee implied as much, and in American Masters (1985), season twenty-six, episode three "Hey, Boo: Harper Lee & to Kill a Mockingbird", it was stated that Dill was the only character which Lee admitted to have fully based on a real person.

Mary Badham, at age nine during filming, became the youngest girl to receive an Oscar nomination (for Best Actress in a Supporting Role), coincidentally losing the award to another child actress, Patty Duke, at age fourteen, for The Miracle Worker (1962).

The piano in Elmer Bernstein's score was played by John Williams.

James Earl Jones auditioned for the role of Tom Robinson.

Horton Foote was initially reluctant to adapt the novel into a screenplay, as he felt that he would be unable to do it justice.

Mary Badham (Scout) messed up nearly every take in which the family eats at the table. Phillip Alford (Jem) did not like eating the same meal dozens of times, so in one of the takes of the scene, in which he rolls Badham in the tire, he aimed it at an equipment truck in an attempt to hurt her.

Finch was writer Harper Lee's mother's maiden name.

The courthouse that was copied for this film still stands in Monroeville, Alabama, and is now a museum dedicated to the book, this movie, and the life of Nelle Harper Lee, and the people represented in this work. Additionally, the town of Monroeville (population, approximately seven thousand) produces a community play based on the book, held on the grounds of the courthouse, and inside the courtroom, every year. The play receives rave reviews, an achievement given that there are no trained actors in it, and has been performed by the Monroeville cast at The Kennedy Center, and in Israel. Tickets typically sell out just a few hours after going on sale. The town contains several historic markers bearing information on Lee and Truman Capote. The courthouse is no longer used for actual court proceedings. Much of it is not air-conditioned nor heated, a function of its old age. A new courthouse stands adjacent to it in the town's square.

Despite the novel's winning the Pulitzer Prize, the studios were not interested in securing the film rights, since they felt that it lacked action and romance (with the absence of a love story), and that the villain does not get a big comeuppance. Producer Alan J. Pakula disagreed, however, and persuaded Director Robert Mulligan, his producing partner at that time, that it would make a good film for their Pakula-Mulligan Productions. Together, they were able to convince Gregory Peck, who readily agreed to the role.

Gregory Peck journeyed to Monroeville, Al, with Robert Mulligan and Alan J. Pakula to meet Harper Lee's ailing father. True to the story, Amasa Lee really had been a widower who raised his children by himself, and at the same time was ready to defend a black man accused of crimes he did not commit. The experience of meeting the actual man aided Peck's performance immeasurably.

With the death of Rosemary Murphy (Maudie Atkinson) on Saturday, July 5th, 2014, Robert Duvall (Arthur "Boo" Radley) is (or was) the film's last surviving adult cast member.

Robert Mulligan's way of handling his child cast members was to let them play together, while keeping the cameras as unobtrusive as possible.

Robert Mulligan and Alan J. Pakula travelled to Harper Lee's hometown of Monroeville, Alabama, but found it unsuitable for filming because the town had been modernized. Therefore, the production team constructed their own ideal version of Monroeville, Alabama, on a backlot at Universal. When Lee saw their re-creation, she said it was perfect.

When he attended the Academy Awards, Gregory Peck was convinced that his friend Jack Lemmon would win the Best Actor Oscar for his searing portrayal of an alcoholic in Days of Wine and Roses (1962). In reality, Gregory Peck was stunned when he heard that he was the winner of the much coveted trophy.

Although Gregory Peck's inspirational performance as Atticus Finch turned out to be a perfect highlight to his long career, Rock Hudson, Universal's number one star at the time, lobbied for the role, and was considered by Alan J. Pakula and Robert Mulligan. Spencer Tracy was the first choice of Pakula and Mulligan, but it conflicted with Tracy's existing film schedule. James Stewart was also offered the part, reportedly second, but told the producers he believed the script was "too liberal", and feared the film would be controversial.

Every day that she shot, Ruth White spent four hours getting into old age make-up, but in the end, most of her scenes were cut from the film, as they tended to slow it up.

In 2007 the American Film Institute ranked this as the #25 Greatest Movie of All Time.

Gregory Peck's grandson Harper Peck Voll was named after Harper Lee.

Art Directors Alexander Golitzen and Henry Bumstead had an entire reconstruction of the fictional town of Maycomb, Alabama, built on the Universal backlot at a cost of two hundred twenty-five thousand dollars. The set contained more than thirty buildings. It would have cost at least one hundred thousand dollars more, had Golitzen and Bumstead not learned of some Southern-style housing about to be demolished to make way for a new Los Angeles freeway. They bought a dozen of them and had them brought to the studio. Such efforts resulted in the two winning the Oscar for Best Art Direction the following year.

Despite the closeness of their characters, Mary Badham and Phillip Alford did not get along while filming. Mary would mimic Phillip saying his lines off camera so that he couldn't concentrate. However, it might not have been malice on her part. In the scene where Atticus drives with the children to speak with Helen Robinson, Mary is mouthing Gregory Peck's lines (at 0:44:37). It seems unlikely that she was trying to break Gregory Peck's concentration. It's possible instead that she memorized everyone's lines in each of her scenes, and she wouldn't know what her next line would be until she recited the line immediately preceding it.

Ranked #2 on the American Film Institute's 100 Most Inspiring Movies of All Time (2006).

Writer Harper Lee owned a percentage of the production, and spent about three weeks on the production set at Universal Studios.

Phillip Alford had trouble eating certain foods for years afterwards, particularly bacon and eggs, as they had to eat their breakfasts repeatedly until they got the scenes right.

The courtroom is a re-creation of the interior of the Monroe County Courthouse in Monroeville, Alabama, Harper Lee's hometown. Prior to filming, Production Designers travelled to Monroeville, took photographs and measurements, and created a near duplicate on a soundstage at Universal Studios. It won Art Directors Alexander Golitzen and Henry Bumstead and Set Decorator Oliver Emert the Academy Award for Best Art Direction-Set Decoration, Black-and-White, 1963.

Ranked #1 on the American Film Institute's list of the ten greatest films in the genre "Courtroom Drama". (June 2008)

It was Horton Foote who recommended Robert Duvall as Arthur "Boo" Radley. Duvall had starred in "The Midnight Caller" at the Neighborhood Playhouse.

Grossed over $13 million in its U.S. release.

According to Brock Peters, the producers were reluctant to cast him, because he had been typecast as a villain.

When Gregory Peck was first approached by Alan J. Pakula and Robert Mulligan for the role of Atticus Finch, Peck had already seen their first collaboration, Fear Strikes Out (1957), and was suitably impressed.

Cast members Mary Badham (Scout), Robert Duvall (Boo), Frank Overton (Heck Tate), Collin Wilcox Paxton (Mayella), and William Windom (Mr. Gilmer) appeared on The Twilight Zone (1959).

The first of six films Robert Mulligan made with his producer partner, Alan J. Pakula, through their Pakula-Mulligan Productions.

Premiered at the famed Radio City Music Hall in New York City.

Bob Ewell's full name is Robert E. Lee Ewell. This is a reference to Gen. Robert E. Lee, the commanding general of the Confederate States of America's army during the Americzn Civil War, also known as the War Between the States.

Film debut of Alice Ghostley.

Film debut of William Windom.

The residential street where the Finches lived was located slightly southeast of Universal's Courthouse Square. It ran in a westerly direction, then hair-pinned towards the back of the courthouse edifice from Mrs. Dubose's corner, on what is now the small parking lot where Royal Crescent Drive and James Stewart Avenue converge.

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

Robert Duvall and John Megna appeared in The Godfather: Part II (1974), but shared no scenes, for two reasons: Megna played the young Hyman Roth in the scenes with Robert De Niro, and his scenes were deleted from the theatrical version of the film. They were restored for a television airing.

The band "The Boo Radleys", who had hits in the 1990's such as "Wake Up Boo!", took inspiration for their name from the original book.

The main production companies for the film were Pakula-Mulligan Productions, owned by Alan J. Pakula and Robert Mulligan, and Brentwood Productions, owned by Gregory Peck. The same production companies also collaborated on Captain Newman, M.D. (1963).

Paul Fix (portrayed Judge Taylor), Brock Peters (portrayed Tom Robinson), John Megna (portrayed Dill Harris), Frank Overton (portrayed Heck Tate), William Windom (portrayed Mr. Gilmer), Richard Hale (portrayed Nathan Radley), and Noble 'Kid' Chissell (portrayed Courtroom Spectator), appeared on Star Trek (1966).

Mary Badham, the youngest at age nine to receive an Oscar nomination (for Best Actress in a Supporting Role), lost to 14-year-old Patty Duke for The Miracle Worker (1962). Both films are based on women who were born in small towns in Alabama.

The Maycomb County Bank calendar in the background when Atticus throws a glass to Tom shows a 30-day month starting on Tuesday. June and September are the only summer months having exactly 30 days, but in September the children would have been in school rather than at the trial. The film is depicting a year when June started on Tuesday. June started on Wednesday in 1932, on Thursday in 1933, on Friday in 1934, on Saturday in 1935, on Monday in 1936 and on Tuesday in 1937, so the film is set from 1936-37 (or else the filmmakers had a different or incorrect calendar).

Gregory Peck and Robert Duvall were born in San Diego, California.

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

In both manner and appearance, Arthur "Boo" Radley (Robert Duvall) is nearly identical to Karl (Billy Bob Thornton) in Sling Blade (1996). Duvall played Karl's father in Sling Blade (1996).

This was Robert Duvall's first credited feature film (non-television) role since his uncredited feature film debut as an MP in Somebody Up There Likes Me (1956).

When Mayella Ewell is sworn in during the trial of Tom Robinson, if you look closely you can see that she does not actually place her hand on the Bible. Instead, she lets it hover just above, as she knows that the testimony she was about to give accusing Tom of assault was false.

Gregory Peck stated in subsequent interviews that he believed what won him the Academy Award was the scene where he quietly walks out of the courthouse after losing the case, while the upper gallery stands in silent respect, and the reverend says, "Miss Jean Louise, stand up. Your father's passing."