An antiquarian or antiquary (from Latin antiquarius 'pertaining to ancient times') is an aficionado or student of antiquities or things of the past. More specifically, the term is used for those who study history with particular attention to ancient artefacts, archaeological and historic sites, or historic archives and manuscripts. The essence of antiquarianism is a focus on the empirical evidence of the past, and is perhaps best encapsulated in the motto adopted by the 18th-century antiquary Sir Richard Colt Hoare, "We speak from facts, not theory."

The Oxford English Dictionary first cites "archaeologist" from 1824; this soon took over as the usual term for one major branch of antiquarian activity. "Archaeology", from 1607 onwards, initially meant what is now seen as "ancient history" generally, with the narrower modern sense first seen in 1837.

Today the term "antiquarian" is often used in a pejorative sense, to refer to an excessively narrow focus on factual historical trivia, to the exclusion of a sense of historical context or process. Few today would describe themselves as "antiquaries", but some institutions such as the Society of Antiquaries of London (founded in 1707) retain their historic names. The term "antiquarian bookseller" remains current for dealers in more expensive old books.

During the Song dynasty (960–1279), the scholar Ouyang Xiu (1007–1072) analyzed alleged ancient artefacts bearing archaic inscriptions in bronze and stone, which he preserved in a collection of some 400 rubbings. Patricia Ebrey writes that Ouyang pioneered early ideas in epigraphy.

The Kaogutu (考古圖) or "Illustrated Catalogue of Examined Antiquity" (preface dated 1092) compiled by Lü Dalin (呂大臨) (1046–1092) is one of the oldest known catalogues to systematically describe and classify ancient artefacts which were unearthed. Another catalogue was the Chong xiu Xuanhe bogutu (重修宣和博古圖) or "Revised Illustrated Catalogue of Xuanhe Profoundly Learned Antiquity" (compiled from 1111 to 1125), commissioned by Emperor Huizong of Song (r. 1100–1125), and also featured illustrations of some 840 vessels and rubbings.

Interests in antiquarian studies of ancient inscriptions and artefacts waned after the Song dynasty, but were revived by early Qing dynasty (1644–1912) scholars such as Gu Yanwu (1613–1682) and Yan Ruoju (1636–1704).

In ancient Rome, a strong sense of traditionalism motivated an interest in studying and recording the "monuments" of the past; the Augustan historian Livy uses the Latin monumenta in the sense of "antiquarian matters." Books on antiquarian topics covered such subjects as the origin of customs, religious rituals, and political institutions; genealogy; topography and landmarks; and etymology. Annals and histories might also include sections pertaining to these subjects, but annals are chronological in structure, and Roman histories, such as those of Livy and Tacitus, are both chronological and offer an overarching narrative and interpretation of events. By contrast, antiquarian works as a literary form are organised by topic, and any narrative is short and illustrative, in the form of anecdotes.

Major antiquarian Latin writers with surviving works include Varro, Pliny the Elder, Aulus Gellius, and Macrobius. The Roman emperor Claudius published antiquarian works, none of which is extant. Some of Cicero's treatises, particularly his work on divination, show strong antiquarian interests, but their primary purpose is the exploration of philosophical questions. Roman-era Greek writers also dealt with antiquarian material, such as Plutarch in his Roman Questions and the Deipnosophistae of Athenaeus. The aim of Latin antiquarian works is to collect a great number of possible explanations, with less emphasis on arriving at a truth than in compiling the evidence. The antiquarians are often used as sources by the ancient historians, and many antiquarian writers are known only through these citations.