Palmyra (/pælˈmaɪrə/ pal-MY-rə; Palmyrene: 𐡶𐡣𐡬𐡥𐡴‎ (), romanized: Tadmor; Arabic: تَدْمُر, romanized: Tadmur) is an ancient city in central Syria. It is located in the eastern part of the Levant, and archaeological finds date back to the Neolithic period, and documents first mention the city in the early second millennium BCE. Palmyra changed hands on a number of occasions between different empires before becoming a subject of the Roman Empire in the first century CE.

The city grew wealthy from trade caravans; the Palmyrenes became renowned as merchants who established colonies along the Silk Road and operated throughout the Roman Empire. Palmyra's wealth enabled the construction of monumental projects, such as the Great Colonnade, the Temple of Bel, and the distinctive tower tombs. Ethnically, the Palmyrenes combined elements of Amorites, Arameans, and Arabs. Socially structured around kinship and clans, Palmyra's inhabitants spoke Palmyrene Aramaic, a variety of Western Middle Aramaic, while using Koine Greek for commercial and diplomatic purposes. The Hellenistic period of West Asia influenced the culture of Palmyra, which produced distinctive art and architecture that combined different Mediterranean traditions. The city's inhabitants worshiped local Semitic, Mesopotamian, and Arab deities.

By the third century, Palmyra had become a prosperous regional center. It reached the apex of its power in the 260s, when the Palmyrene King Odaenathus defeated the Sasanian emperor Shapur I. The king was succeeded by queen regent Zenobia, who rebelled against Rome and established the Palmyrene Empire. In 273, Roman emperor Aurelian levelled the city, which was later restored by Diocletian at a reduced size. The Palmyrenes converted to Christianity during the fourth century and to Islam in the centuries following the conquest by the seventh-century Rashidun Caliphate, after which the Palmyrene and Greek languages were replaced by Arabic.

Before 273 CE, Palmyra enjoyed autonomy and was attached to the Roman province of Syria, having its political organization influenced by the Greek city-state model during the first two centuries CE. The city became a Roman colonia during the third century, leading to the incorporation of Roman governing institutions, before becoming a monarchy in 260. Following its razing in 273, Palmyra became a minor center under the Byzantines and later empires. Its destruction by the Timurids in 1400 reduced it to a small village. Under French Mandatory rule in 1932, the inhabitants were moved into the new village of Tadmur, and the ancient site became available for excavations. During the Syrian civil war in 2015, the Islamic State captured Palmyra and destroyed large parts of the ancient city, which was recaptured by the Syrian Army on 2 March 2017. It was then recaptured by the Syrian Free Army, after the fall of the Assad government in December 2024.

Records of the name "Tadmor" date from the early second millennium BC; 18th-century BC tablets from Mari written in cuneiform record the name as "Ta-ad-mi-ir", while Assyrian inscriptions of the 11th century BC record it as "Ta-ad-mar". Aramaic Palmyrene inscriptions themselves showed two variants of the name; TDMR (i.e., Tadmar) and TDMWR (i.e., Tadmor). The etymology of the name is unclear; the standard interpretation, supported by Albert Schultens, connects it to the Semitic word for "date palm", tamar (תמר‎), thus referring to the palm trees that surrounded the city.

The Greek name Παλμύρα (Latinized Palmyra) was first recorded by Pliny the Elder in the first century AD. It was used throughout the Greco-Roman world. It is generally believed that "Palmyra" derives from "Tadmor" and linguists have presented two possibilities; one view holds that Palmyra was an alteration of Tadmor. According to the suggestion by Schultens, "Palmyra" could have arisen as a corruption of "Tadmor", via an unattested form "Talmura", changed to "Palmura" by the influence of the Latin word palma (date "palm"), in reference to the city's palm trees, then the name reached its final form "Palmyra". The second view, supported by some philologists, such as Jean Starcky, holds that Palmyra is a translation of "Tadmor" (assuming that it meant palm), which had derived from the Greek word for palm, "palame".

An alternative suggestion connects the name to the Syriac tedmurtā (ܬܕܡܘܪܬܐ) "miracle", hence tedmurtā "object of wonder", from the root dmr "to wonder"; this possibility was mentioned favourably by Franz Altheim and Ruth Altheim-Stiehl (1973), but rejected by Jean Starcky (1960) and Michael Gawlikowski (1974). Michael Patrick O'Connor (1988) suggested that the names "Palmyra" and "Tadmor" originated in the Hurrian language. As evidence, he cited the inexplicability of alterations to the theorized roots of both names (represented in the addition of -d- to tamar and -ra- to palame). According to this theory, "Tadmor" derives from the Hurrian word tad ("to love") with the addition of the typical Hurrian mid vowel rising (mVr) formant mar. Similarly, according to this theory, "Palmyra" derives from the Hurrian word pal ("to know") using the same mVr formant (mar).

The city of Palmyra lies 215 km (134 mi) northeast of the Syrian capital, Damascus; along with an expanded hinterland of several settlements, farms, and forts, the city forms part of the region known as Palmyrena or Palmyrene. The city is located in an oasis surrounded by palms (of which twenty varieties have been reported). Two mountain ranges overlook the city - the northern Palmyrene mountain belt from the north and the southern Palmyrene mountains from the southwest. In the south and the east Palmyra is exposed to the Syrian Desert. A small wadi, al-Qubur, crosses the area, flowing from the western hills past the city before disappearing in the eastern gardens of the oasis. South of the wadi is a spring, Efqa. Pliny the Elder described the town in the 70s AD as famous for its desert location, for the richness of its soil, and for the springs surrounding it, which made agriculture and herding possible.