The Parsis or Parsees (/ˈpɑːrsiz/) are a Zoroastrian ethnic group in the Indian subcontinent. They are descended from Persian refugees who migrated to the Indian subcontinent during and after the Arab-Islamic conquest of Iran in the 7th century, when Zoroastrians were persecuted by the early Muslims. Representing the elder of the Indian subcontinent's two Zoroastrian communities, the Parsi people are culturally, linguistically, and socially distinct from the Iranis, whose Zoroastrian ancestors migrated to British-ruled India from Qajar-era Iran. The word Parsi is derived from the Persian language, and literally translates to Persian (پارسی, Pārsi).

According to the 16th-century Parsi epic Qissa-i Sanjan, fleeing persecution, the Zarthushti (Zoroastrian) Persians, citizens of the Sassanian empire sought refuge in the Indian subcontinent. This migration from different parts of the Sassanian empire continued between the 8th century and the 10th century. The earliest of these migrants settled among the Hindus of present-day Gujarat after being granted refuge by Rajput King Jadhav Rana, the king of Sanjan.

Zoroastrianism (Zarathushti Pantha) had served as Iran's state religion since at least the time of the Achaemenid Empire. However, the conquest of the Sasanian Empire by the Rashidun Caliphate marked the beginning of the Islamisation of Iran, which prompted much of the Zoroastrian-majority population to either convert to Islam or flee, though a number of Iranian figures stayed in active revolt against the Rashidun army and the later Islamic caliphates for almost 500 years after the collapse of the Sasanian Empire. Nevertheless, Zoroastrianism continued to decline, and most Iranians had become Muslims by the 10th century, shifting the concentration of the religion's followers away from the Iranian plateau for the first time in recorded history.

The Gujarati-speaking Parsi community accounts for the oldest sustained presence of Zoroastrianism in India, and is legally differentiated from the Dari-speaking Irani community on the basis of their origin (Sanjan and Navsari in Central Asia) and the era of their migration to the country. Despite this legal distinction, the terms "Parsi" and "Zoroastrian" are commonly used interchangeably to denote both communities, which make up the world's largest Zoroastrian population. Notably, no substantial differences exist between Parsi and Irani religious principles, convictions, and customs.

According to the Encyclopædia Britannica,

Parsi, also spelled Parsee, member of a group of followers in India of the Persian prophet Zoroaster. The Parsis, whose name means "Persians", are descended from Persian Zoroastrians who emigrated to India to avoid religious persecution by the Muslims. They live chiefly in Mumbai and in a few towns and villages mostly to the south of Mumbai, but also a few minorities nearby in Karachi (Pakistan) and Chennai. There is a sizeable Parsee population in Pune as well in Bangalore. A few Parsee families also reside in Kolkata and Hyderabad. Although they are not, strictly speaking, a caste, since they are not Hindus, they form a well-defined community. The exact date of the Parsi migration is unknown. According to tradition, the Parsis initially settled at Hormuz on the Persian Gulf but finding themselves still persecuted they set sail for India, arriving in the 8th century. The migration may, in fact, have taken place as late as the 10th century, or in both. They settled first at Diu in Kathiawar but soon moved to South Gujarāt, where they remained for about 800 years as a small agricultural community.

The term Pārsi, which in the Persian language is a demonym meaning "inhabitant of Pārs" and hence "ethnic Persian", is not attested in Indian Zoroastrian texts until the 17th century. Until that time, such texts consistently use the Persian-origin terms Zartoshti "Zoroastrian" or Vehdin "[of] the good religion". The 12th-century Sixteen Shlokas, a Sanskrit text in praise of the Parsis, is the earliest attested use of the term as an identifier for Indian Zoroastrians.

The first reference to the Parsis in a European language is from 1322, when a French monk, Jordanus, briefly refers to their presence in Thane and Bharuch. Subsequently, the term appears in the journals of many European travelers, first French and Portuguese, later English, all of whom used a Europeanized version of an apparently local language term. For example, Portuguese physician Garcia de Orta observed in 1563 that "there are merchants ... in the kingdom of Cambaia ... known as Esparcis. We Portuguese call them Jews, but they are not so. They are Gentios." In an early 20th-century legal ruling (see self-perceptions, below), Justices Davar and Beaman asserted (1909:540) that "Parsi" was also a term used in Iran to refer to Zoroastrians. notes that in much the same way as the word "Hindu" was used by Iranians to refer to anyone from the Indian subcontinent, "Parsi" was used by the Indians to refer to anyone from Greater Iran, irrespective of whether they were actually ethnic Persian people. In any case, the term "Parsi" itself is "not necessarily an indication of their Iranian or 'Persian' origin, but rather as indicator – manifest as several properties – of ethnic identity". Moreover, if heredity were the only factor in a determination of ethnicity, the Parsis would count as Parthians according to the Qissa-i Sanjan.