I) The Form

  a} The characters
In The Monk, there are characters from the Catholic Church like monks and nuns : Ambrosio, the main character, Matilda, Agnes, the Prioress etc.
The "good people" are constituted by young noblemen (Don Raymond, Don Lorenzo and young ladies : Don Raymond and Agnes, Don Lorenzo and Antonia.
There are supernatural beings, ghosts and demons,  : Lucifer, the Bleeding Nun, the Wandering Jew and Matilda.
Ambrosio, the main character, has two faces : a virtuous monk and a horrible monster. This duality is similar to that of Doctor Jekyll and Mister Hyde.

-The main characters of Dracula are : Jonathan and Mina Harker, doctor Abraham Van Helsing, Arthur Holmwood, John Seward, Quincey Morris and Lucy against the Count Dracula, a vampire.
-Doctor Jekyll and Mister Hyde contains several characters : doctor Henry Jekyll (and "mister Hyde"), Gabriel John Utterson, doctor Hastie Lanyon, mister Poole and Richard Enfield.
-In Frankenstein, the main characters are Victor Frankenstein, his creature, Robert Walton, Alphonse Frankenstein (the father), and William (the young brother).


  b} The places
The story of The Monk takes place in a sinister monastery/convent/abbey and sometimes in a cemetery, in Spain.
-In Dracula, the main places are the Count's castle, in Transylvania, and in London.
-In Doctor Jekyll and Mister Hyde, the story takes place in London.
-Frankenstein takes place in Germany (the laboratory), in Switzerland, London and Scotland. It is like the Frankenstein's travel in Europe.

II) The Content
 
  a} The topics
Downfall of Ambrosio, curse, rape, murder, incest, romance, sexual desire, sorcery and satanism (Matilda), prophecy, fate/doom, secrets, death, cruelty.

- Supernatural in The Monk is the main topic : there are a lot of supernatural events and characters, like Lucifer, Matilda (she is a demon), the Bleeding Nun, the Wandering Jew, the mother of Antonia who becomes a ghost after her death, ritual, exorcizing and witchcraft.

-Dracula's story tells about a vampire, the eternity, and supernatural powers in general. There are clearly supernatural events, throughout the story.
-In Doctor Jekyll and Mister Hyde, Dr Jekyll liberates his evil self with the help of the science : it is a supernatural thing more than a real scientific possibility.
-In Frankenstein, a doctor create "life"  Like Doctor Jekyll and Mister Hyde, it is not really something scientific.

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- Progress : In The Monk, there is an opposition between the progress (Industrial Revolution, progress in science, Victorian Era etc.) and the remnants of the past, such as the old catholic religion and its secrets, its old monasteries, like the one from The Monk, etc.

-In Dracula, recent inventions such as the telegraph or the typewriter, are used as tools to counter Count Dracula's dark projects. Also, London is the  place where Industrial revolution began, and Transylvania is a backward, mainly peasant country, with old beliefs.
-For Doctor Jekyll and Mister Hyde, the progress is mostly scientific : the main plot is based on a doctor (science) who creates a potion (science). The story revealed the fear that many people have about the advancement of science in the Victorian Era.
-Same as Doctor Jekyll and Mister Hyde, Frankenstein is based on the excesses of science : with the science, the human plays God and create life/monster.

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- Human Nature : In The Monk, Ambrosio gives free rein to his deepest vices : rape (Antonia), murder (Antonia and her mother), sexual desire (Matilda, Antonia) while he made vow of chastity, because he is a monk.

-Count Dracula is very selfish : he kills people only to prolong his own life. Also, Quincey Morris, Arthur Holmwood and John Seward want to destroy Dracula because of the loss of Lucy : they want to avenge her.
-Dr Jekyll creates a potion that turns him into a monster. He is a gentleman the day, and become a monster at the night. Thereby, Jekyll is not "responsible" of what Hyde is doing the night. By his way, he does not feel guilty for the horrible acts he commits the night.
-The creature from Frankenstein is innocent and pure, but due to the people who judge him by his appearance and despite his efforts to be nice and be accepted by the humans, he is rejected, even by his creator (doctor Victor Frankenstein). The "monster" realize that he will never be accepted because of his appearance.

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- Romance : In The Monk, there are several relationships : Ambrosio and Matilda, and Antonia ; Don Raymond and Agnes ; and Don Lorenzo and Antonia.

-In Dracula, the romance is very present, with seduction and relationships. Jonathan Harker and Mina, his fiancée ; Quincey Morris, Arthur Holmwood and John Seward, both love Lucy. Also, Count Dracula tries to seduce Mina several times.

-Surprisingly, there are neither relationships nor women characters in Doctor Jekyll and Mister Hyde. There are only men in the story.
-In Frankenstein, the creature asks Victor Frankenstein to create a wife for him, so he could live in a peaceful atmosphere. But Victor refuses, so the monster kills Victor's wife, Elizabeth.

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b} The Atmosphere
The atmosphere in The Monk is really gloomy, dark, horrifying, uneasy, dreadful, sinister, creepy, because of all the murders, rapes, evil presence, the old monastery, the secrets etc.

-In Dracula, the Count's castle and his evil presence, the secrets of Transylvania, the night, the supernatural powers of Dracula and his goals, the dark streets of London make the atmosphere really uneasy.
-Frankenstein plot is initially gloomy : a man who creates the life, who creates a monster and abandon it. The abandon and the reject, from the humans, of the creature is something really sad, because it was pure and innocent before becoming a murderer.
-The story of Doctor Jekyll and Mister Hyde has also an atmosphere sinister : in the London's night, mister Hyde is unleashed and does whatever he wants, like murdering people. It's really creepy.

Conclusion :

The Monk contains all the characteristics of a gothic fiction : the heroes are gentlemen/noblemen, there are evil/supernatural beings and events, relationships/romance, references to the progress of the Victorian Era, reflexions on the human nature, gloomy places, and a typical gothic atmosphere (dark, gloomy, frightening).
The Monk is definitely a work of gothic fiction.