Suspiria is a 1977 Italian supernatural horror film directed by Dario Argento, who co-wrote the screenplay with Daria Nicolodi, partially based on Thomas De Quincey's 1845 essay Suspiria de Profundis. The film stars Jessica Harper as an American ballet student who transfers to a prestigious European dance academy but realizes, after a series of murders, that the academy is a front for a coven of witches. It also features Stefania Casini, Flavio Bucci, Miguel Bosé, Alida Valli, Udo Kier, and Joan Bennett, in her final film role.

The film is the first of the trilogy Argento refers to as The Three Mothers, which also comprises Inferno (1980) and The Mother of Tears (2007). Suspiria has received a positive response from critics for its visual and stylistic flair, use of vibrant colors and its score by Argento and the progressive rock band Goblin.

Suspiria was nominated for two Saturn Awards: Best Supporting Actress for Bennett in 1978, and Best DVD Classic Film Release in 2002. It is recognized as one of the most influential films in the horror genre and has received acclaim from critics in retrospective reviews. It served as the inspiration for a 2018 film of the same title, directed by Luca Guadagnino.

Suzy Bannion, a young American ballet student, arrives in Freiburg, West Germany, to study at the co-ed Tanz Akademie, a prestigious dance school. She sees another student, Pat Hingle, flee the school in terror. Suzy is refused entry to the school and forced to stay in town overnight. Pat takes refuge at a friend's apartment and tells her that something sinister happened at the school. Pat is ambushed by a shadowy figure who stabs her repeatedly before hanging her with a noose by throwing her through the apartment building's skylight. Pat's friend is also killed after being impaled by a falling shard of glass while trying to alert other tenants to the murder.

Suzy returns to the school the next morning, where she meets Miss Tanner, the head instructor, and Madame Blanc, the deputy headmistress. Tanner introduces Suzy to Pavlos, one of the school's servants. She also meets classmates Sara and Olga, her new roommate. Suzy experiences an unsettling encounter with one of the school's matrons and Blanc's nephew, Albert, before passing out during a dance class. When she regains consciousness, Suzy learns that Olga has thrown her out of her apartment, forcing her to live at the school with Sara in the room next door.

One night, maggots fall from the ceilings of the students' rooms due to a shipment of spoiled food in the attic, forcing them to sleep in one of the dance studios. During the night, a woman enters the room but is obscured by a curtain hung around the room's perimeter. Sara, frightened by her hoarse and labored breathing, recognizes her as the school's headmistress, who is supposedly out of town. The next day, the school's blind pianist, Daniel, is abruptly fired by Miss Tanner when his German Shepherd bites Albert. Daniel is stalked by an unseen force while walking through a plaza that night; his dog turns on him and viciously rips out his throat.

Sara tells Suzy that she was the one on the intercom who refused her entry the night Pat was murdered. She reveals that Pat was behaving strangely before her death and promises to show Suzy the notes that she left behind. Sara finds that Pat's notes are missing and is forced to flee when an unseen assailant enters the room. They pursue her through the school before cornering her in the attic. She escapes through a small window but falls into a pit of razor wire, entangling her before her pursuer kills her by slashing her throat.

The next morning, Tanner tells Suzy that Sara has fled the school. Suspicious, Suzy contacts Sara's friend and former psychiatrist, Frank Mandel. He reveals that the school was established in 1895 by Greek émigrée Helena Markos, who was allegedly a witch. Suzy also consults with Professor Milius, a professor of the occult. He reveals that a coven of witches draws its strength and power from its leader, and without a leader, the coven will perish.