Quiriguá (Spanish pronunciation: [kiɾiˈɣwa]) is an ancient Maya archaeological site in the department of Izabal in south-eastern Guatemala. It is a medium-sized site covering approximately 3 square kilometres (1.2 sq mi) along the lower Motagua River, with the ceremonial center about 1 km (0.6 mi) from the north bank. During the Maya Classic Period (AD 200–900), Quiriguá was situated at the juncture of several important trade routes. The site was occupied by 200, construction on the acropolis had begun by about 550, and an explosion of grander construction started in the 8th century. All construction had halted by about 850, except for a brief period of reoccupation in the Early Postclassic (c. 900 – c. 1200). Quiriguá shares its architectural and sculptural styles with the nearby Classic Period city of Copán, with whose history it is closely entwined.

Quiriguá's rapid expansion in the 8th century was tied to king K'ak' Tiliw Chan Yopaat's military victory over Copán in 738. When the greatest king of Copán, Uaxaclajuun Ub'aah K'awiil or "18-Rabbit", was defeated, he was captured and then sacrificed in the Great Plaza at Quiriguá. Before this, Quiriguá had been a vassal state of Copán, but it maintained its independence afterwards. The ceremonial architecture at Quiriguá is quite modest, but the site's importance lies in its wealth of sculpture, including the tallest stone monumental sculpture ever erected in the New World. Because of its historical importance, the site of Quiriguá was inscribed on the UNESCO World Heritage List in 1981.

The archaeological site of Quiriguá is named after the nearby village of the same name, and is located a little over 200 km (120 mi) northeast of Guatemala City; it lies in the municipality of Los Amates in the department of Izabal and has an elevation of 75 m (246 ft) above mean sea level.

Positioned on the north bank of the lower reaches of the Motagua River, Quiriguá is situated at the point where the valley broadens into a flood plain, which has exposed the site to periodic flooding over the centuries. Although the river passed close to the site during the period of the city's occupation, it has since changed course and now flows 1 km (0.6 mi) south of the ceremonial centre. Quiriguá is 48 km (30 mi) north of Copán, and is located 15.7 km (9.8 mi) north-west of the international border with Honduras.

The local bedrock is a hard red sandstone, which the inhabitants used in the construction of monuments and architecture. This local sandstone is very strong and not prone to shearing or fracturing, allowing the sculptors at Quiriguá to erect the tallest freestanding stone monuments in the Americas. Quiriguá was built directly over the Motagua Fault and the city suffered damage in ancient times as a result of major earthquakes.

Although the Quiriguá elite were clearly Maya in ethnicity, the site lies on the southern periphery of the Mesoamerican area and the population was at least bi-ethnic, with ethnic Maya in a minority. The majority of the population belonged ethnically to the less complex Intermediate Area lying beyond the eastern border of Mesoamerica. The population density of the site has been estimated at 400 to 500 per square kilometer (1040 to 1300 per square mile) in the centre of the city during the Late Classic with an estimated peak population of 1200–1600; surveys have revealed an average of 130 structures per square kilometer (338 per square mile) at the site, compared with 1449 structures/km² (3767 per square mile) in central Copán. The low population density indicates that Quiriguá served as the focus for a dispersed rural population.

The population levels of the Quiriguá valley increased rapidly after the successful rebellion against Copán in 738, although it was never a heavily populated site. In the 9th century there was a severe decline in population, culminating in the abandonment of the city.

The Motagua River flows down from the western Guatemalan highlands, and Quiriguá was ideally positioned to control the trade of uncut jade, the majority of which was found in the middle reaches of the Motagua Valley, as well as controlling the flow of other important commodities up and down the river such as cacao, which was produced as a local cash crop. Although cacao was produced for trade, maize remained the primary local crop due to its central role in the Maya diet. In addition, maize probably formed an important component in the site's tribute payments to its overlords at Copán, a city that was exhausting its own local resources. Although little jade has been recovered from the site, there is evidence for trade in obsidian originating from the Ixtepeque source situated near the upper reaches of the Motagua.