Twice, Enola offers laboring boys £5 for their clothing. £5 in 1880 would be the equivalent of approximately £350 (US$455) in 2020. However, the buying power would be much greater: a common laborer earned about 3s 9d (three shillings and 9 pence) per week, or £9.15s., per year. Thus, Enola has offered a half a year's salary to the laborers for their clothes.

Millie Bobby Brown and her sister Paige, being fans of the books, approached author Nancy Springer with the intention to star and produce the film under their own label, however Millie Bobby found a financial backer in the form of Legendary Entertainment who offered financing while she was filming Godzilla: King of the Monsters (2019) for the company. For this film, Millie Bobby was paid $6 million for her starring role and an additional $500,000 as a producer fee.

Enola and her mother are shown practicing beekeeping, a hobby later taken up by her brother Sherlock upon his retirement.

Millie Bobby Brown is one of the youngest actresses to have a Producer credit at age 16.

Based on the Nancy Springer book series "The Enola Holmes Mysteries," which follows Sherlock and Mycroft Holmes' much younger sister, Enola.

No reference to a younger sister was ever made in the original Doyle stories. Some readers have speculated that there could be another Holmes sibling, citing the fact that Sherlock never mentioned that he had a brother (Mycroft) until he showed up at Baker Street.

During the montage of images introducing Sherlock Holmes, Henry Cavill's head is superimposed on an original illustration of Holmes by Sidney Paget.

Canonically, Sherlock himself describes Mycroft as the smartest sibling by far but is also extremely "lazy." In this adaptation, he is described as "bitter" for lacking Sherlock's investigative skills.

Tewkesbury's uncle served in the Afghan War. This is the same war in which Dr. Watson hurt his leg, from which he was recuperating as the Conan Doyle stories began.

Although Sam Claflin is playing the eldest Holmes sibling, he is three years younger than Henry Cavill.

In June 2020, some controversy arose around the portrayal of Sherlock Holmes as being too caring and empathetic in this film version, with Arthur Conan Doyle's estate suing Netflix and Nancy Springer (the author of the books this movie is based on) for copyright infringement, as the source stories are not yet in the public domain. In their suit, filed in a New Mexico court, they explained "(The) copyright infringement arises from defendants unauthorized copying of original creative expression by (Doyle) in copyrighted Sherlock Holmes stories (sic)." They have listed bosses at Netflix and producers at Legendary Pictures as defendants, alongside Springer, screenwriter Jack Thorne, director Harry Bradbeer, and publishers at Penguin Random House, among others. According to Deadline, estate executives are seeking a jury trial and unspecified damages and relief from further infringement on copyrights. On December 18, 2020, the lawsuit was dismissed with prejudice by stipulation of all parties,

Helena Bonham Carter plays the committed suffragette Eudoria Holmes. In real life, she is the great-granddaughter of H.H. Asquith, who served as the Prime Minister of the United Kingdom from 1908 to 1916, during the height of the suffrage movement. He was a staunch opponent of votes for women.

Miss Harrison's automobile is a Benz Patent-Motorwagen produced from 1886-93 and is widely regarded as the first production automobile. A set of 100 reproductions were commissioned by Mercedes Benz in 2002. This is most likely one of those reproductions.

Based on Dr. Watson's absence, the references to the (3rd) Electoral Reform Bill (circa 1884) and Lestrade's insistence that Sherlock Holmes always works alone, it can be inferred that the story takes place shortly after Holmes and Watson's first meeting in 1882, as depicted in the first canonical Holmes adventure, 'A Study in Scarlet.'

The train used in the movie is a GWR 28XX freight loco, though they are used on passenger trains in preservation. The carriages appear to be genuine period GWR cars.

According to the newspaper, the storyline takes place in 1884.

Originally intended to be a theatrical release by Warner Bros. Pictures. in April 2020, Netflix took over distribution rights to the film due to the COVID-19 pandemic. It was digitally released on September 23, 2020. Unfortunatelly, Warner Bros. had no involvement with this film because it was removed from the Warner Bros. catalog.

For added freedom and flexibility of camera movement, the movie was filmed almost exclusively using the Steadicam system.

According to the canon novels by Sir Arthur Conan Doyle, the first novel written in 1887 says that Sherlock met Dr. Watson in 1881. Watson accompanied Sherlock occasionally. In the movie, set in 1884, Lestrade says Sherlock always works alone. As such, the movie is not in sync with the rest of what is known about Sherlock's life. Enola comes from a series of books written in the early 2000s and would conceivably fit into the canon story.

Frances de la Tour's second appearance in a 'non-canonical' Sherlock Holmes film, following her appearance in Mr. Holmes (2015).

Fiona Shaw played the headmistress of the finishing school that Enola was sent to. Fiona Shaw also played the headmistress of a boarding school/finishing school in Three Men and a Little Lady (1990).

This is Hattie Morahan's third Sherlock Holmes related role; she previously played Jean Leckie in Arthur & George (2015) and Ann Kelmot in Mr. Holmes (2015).

Enola consistently "breaks the fourth wall" by turning to face the camera, and speaking directly to the audience.

A shout out to Jack Thorne, the screenwriter of "Enola Holmes", can be seen in the picture of London at the end of the movie. A red and white hot air balloon is floating above London. Jack Thorne was the screenwriter for "The Aeronauts" which was also set in London in the 1860s.

At around 0:40:47, while Enola is in the boarding house trying to remember which phase of the plan she is on, the last of the title cards, visible for only a few frames, reads "Do I Love Tewkesbury?"

The House of Lords debate on the 1884 Reform Act (or Representation of the People Act as it was formally known) did not pass by 1 vote but was in fact the result of a compromise agreement between the Liberal and Conservative parties, so it would have passed by a wide margin.

In the last scene between Enola and her mother, Eudoria is wearing a bodice which appears to be embroidered with pansies. Much is made of the language of flowers in this film. Pansies mean love and/or admiration and were also adopted as a symbol of the free thought. Each of these meaning apply in this scene the characters themselves, both in terms of their regard for one another and their attitudes.