Jerash or Jarash (Arabic: جرش, romanized: Ǧaraš, Arabic pronunciation: [dʒa.raʃ]; Greek: Γέρασα, romanized: Gérasa, Attic Greek pronunciation: [ɡérasa], Koine Greek pronunciation: [ˈɡerasa]) is a city in northern Jordan. The city is the administrative center of the Jerash Governorate, and has a population of 50,745 as of 2015. It is located 30.0 miles (48.3 kms) north of the capital city Amman.

The earliest evidence of settlement in Jerash is in a Neolithic site known as Tal Abu Sowan, where rare human remains dating to around 7500 BC were uncovered. Jerash flourished during the Greek, Hellenistic, Roman, and Byzantine periods, when it was known as Gerasa. It was one of the cities of the Hellenistic cities of the Decapolis. It was an important city in early Christian times and its early churches, some of which were formerly temples, include notable examples of the evolution of church architecture. In the mid-eighth century the 749 Galilee earthquake destroyed large parts of it, and subsequent earthquakes contributed to additional destruction.

In 1120, Zahir ad-Din Toghtekin, atabeg of Damascus ordered a garrison of forty men to build up a fort in an unknown site of the ruins of the ancient city, likely the highest spot of the city walls in the north-eastern hills. It was captured in 1121 by Baldwin II, King of Jerusalem, and utterly destroyed. The Crusaders immediately abandoned Jerash and withdrew to Sakib (Seecip); the eastern border of the settlement.

Jerash was then deserted and reappeared in the historical record at the beginning of Ottoman rule in the area during the early 16th century. In the census of 1596, it had a population of 12 Muslim households. However, archaeologists found a small Mamluk hamlet in the Northwest Quarter which indicates that Jerash was resettled before the Ottoman era. The excavations conducted since 2011 have shed light on the Middle Islamic period as recent discoveries have uncovered a large concentration of Middle Islamic/Mamluk structures and pottery. The ancient city has been gradually revealed through a series of excavations since 1925.

Jerash today is home to one of the best preserved Greco-Roman cities, which earned it the nickname "Pompeii of the Middle East". Approximately 330,000 visitors arrived in Jerash in 2018, making it one of the most visited sites in Jordan. The city hosts the Jerash Festival, one of the leading cultural events in the Middle East that attracts tens of thousands of visitors every year.

Archaeologists have found ruins of settlements dating back to the Neolithic Age. Moreover, in August 2015, an archaeological excavation team from the University of Jordan unearthed two human skulls that date back to the Neolithic period (7500–5500 BC) at a site in Jerash. This forms solid evidence of inhabitance of Jordan in that period, especially in connection with the existence of 'Ain Ghazal Neolithic settlement in Amman. The importance of the discovery lies in the rarity of the skulls, as archaeologists estimate that a maximum of 12 sites across the world contain similar human remains.

Evidence of settlements dating to the Bronze Age (3200–1200 BC) have been found in the region.

Jerash is the site of the ruins of the Greek city of Gerasa, also referred to as Antioch on the Golden River. Ancient Greek inscriptions from the city support that the city was founded by Alexander the Great and his general Perdiccas, who allegedly settled aged Macedonian soldiers there during the spring of 331 BC, when he left Egypt and crossed Syria en route to Mesopotamia. However, other sources, namely the city's former name of "Antioch on the Chrysorrhoas," point to a founding by Seleucid King Antioch IV, while still others attribute the founding to Ptolemy II of Egypt.