Indo-European studies (German: Indogermanistik) is an interdisciplinary field that examines the Indo-European languages and related cultural history through historical linguistics, comparative philology, archaeology, and genetics.

The discipline coalesced in late eighteenth- and nineteenth-century Europe as comparative linguists including Marcus Zuerius van Boxhorn, Franz Bopp, and August Schleicher refined methods for reconstructing a shared ancestry among the languages. Research centers on rebuilding the Proto-Indo-European language, homeland, and society by combining comparative analysis with archaeological, mythological, and genetic evidence to test models such as the Kurgan hypothesis. Dedicated programs, research centers, journals, and book series sustain Indo-European studies across Europe and North America.

The term Indo-European was coined in 1813 by British scholar Sir Thomas Young to describe a newly discovered family of languages. Young used it as a geographical term to refer to languages spanning from the Indian subcontinent to Europe. At the time, there was no consensus on what to call this language family, and scholars proposed various alternative names:

Rask's term japetisk ("Japhetic languages") derived from Japheth, son of the Biblical Noah. This naming paralleled Semitic (from Noah's son Shem) and Hamitic (from Ham). Both Japhetic and Hamitic are now obsolete terms, though "Hamito-Semitic" occasionally appears as a dated name for the Afro-Asiatic languages.

The term Indo-German entered English usage through J.C. Prichard in 1826, though he favored Indo-European. In French, A. Pictet established indo-européen in 1836. The German term Indogermanisch was introduced by Julius von Klapproth in 1823 to encompass both northern and southern branches of the language family. Franz Bopp used Indoeuropäisch from 1835 onward. August Friedrich Pott's work later popularized Indo-Germanisch, interpreting it to span from the easternmost to westernmost branches. This led to unproductive debates about whether Indo-Celtic or Tocharo-Celtic might be more appropriate names.

In modern usage, Indo-European and indo-européen dominate English and French academic writing. German scholarship primarily uses Indogermanisch, though Indoeuropäisch is gaining prominence. Dutch academic writing has largely transitioned from Indogermaans to Indo-Europees.

Indo-Hittite is sometimes used for the wider family including Anatolian by those who consider that Indo-European (IE) and Anatolian are comparable separate branches.

The ancient Greeks were aware that their language had changed since the time of Homer (about 730 BC). Aristotle (about 330 BC) identified four types of linguistic change: insertion, deletion, transposition and substitution. In the 1st century BC, the Romans were aware of the similarities between Greek and Latin.^{[citation needed]}