Strigoi in Romanian mythology are troubled spirits that are said to have risen from the grave. They are attributed with the abilities to transform into a beast, become invisible, and to gain vitality from the blood of their victims. Bram Stoker's Dracula may be a modern interpretation of the Strigoi through their historic links with vampirism.

Strigòi is a Romanian word that originated from a root related to the Latin terms strix or striga with the addition of the augmentative suffix -oi (feminine -oaică). Otila Hedeşan notes that the same augmentative suffix appears in the related terms moroi and bosorcoi (borrowed from Hungarian boszorka) and considers this parallel derivation to indicate membership in the same "mythological micro-system." The -oi suffix notably converts feminine terms to the masculine gender as well as often investing it with a complex mixture of augmentation and pejoration. The root has been related particularly to owls. Cognates are found throughout the Romance languages, such as the Italian words strega or the Venetian word strìga which mean "witch". The Italian stregone even has the parallel cognate augmentative suffix and means "sorcerer." In French, stryge means a bird-woman who sucks the blood of children. Jules Verne used the term "stryges" in Chapter II of his novel The Carpathian Castle, published in 1892. The Greek word strix, Polish strzyga, Hungarian sztriga, and the Albanian word shtriga are also cognate.

In the late Roman period the word became associated with witches or a type of ill-omened nocturnal flying creature. A strix (Late Latin striga, Greek στρίγξ), referred to night-time entities that craved human flesh and blood, particularly infants'.

It is related to the Romanian verb a striga, which means "to scream".

One of the earliest mentions of a historical strigoi is the story of Jure Grando Alilović (1579–1656) from the region of Istria. The villager is believed to have been the first real person described as a vampire because he was referred to as a strigoi, štrigon or štrigun in contemporary local records. Grando is supposed to have terrorized his former village sixteen years after his death. Eventually he was decapitated by the local priest and villagers. The Carniolan scientist Johann Weikhard von Valvasor wrote about Jure Grando Alilović's life and afterlife in his extensive work The Glory of the Duchy of Carniola when he visited Kringa during his travels. This was the first written document on vampires. Grando was also mentioned in writings by Erasmus Francisci and Johann Joseph von Goerres (La mystique divine, naturelle, et diabolique, Paris 1855), whose story was much more elaborate, full of fantastic details to make the story more interesting and sensational. In modern times, the Croatian writer Boris Perić has researched the legend and written a book (The Vampire) on the story.

Striga are mentioned by the Moldavian statesman and soldier Dimitrie Cantemir in his work Descriptio Moldaviae (1714–1716). He thought that the striga were mostly Moldavian and Transylvanian beliefs. However, he associated them with witches or warlocks rather than blood-drinking undead vampires. The book mentions dunking – a traditional test for witchcraft – as a method of identifying a striga.

An 1865 article on Transylvanian folklore by Wilhelm Schmidt describes the strigoi as nocturnal creatures that preyed on infants. He reports a tradition in which, upon the birth of a child, one tosses a stone behind oneself and exclaims "This into the mouth of the strigoi!"

In 1909, Franz Hartmann mentioned in his article "An Authenticated Vampire Story", published in The Occult Review, that peasant children from a village in the Carpathian Mountains started to die mysteriously. The villagers began to suspect a recently deceased count was a vampire, dwelling in his old fortress. Frightened villagers burned the castle to stop the deaths.