Gijón (Spanish: [xiˈxon] ^ⓘ) or Xixón (Asturian: [ʃiˈʃoŋ]) is a city and municipality in north-western Spain. It is the largest city and municipality by population in the autonomous community of Asturias. It is located on the coast of the Cantabrian Sea in the Bay of Biscay, in the central-northern part of Asturias; it is approximately 24 km (15 mi) north-east of Oviedo, the capital of Asturias, and 26 km (16 mi) from Avilés. With a population of 270,219 as of 2024, Gijón is the 16th-largest city in Spain.

Gijón forms part of a large metropolitan area that includes twenty councils in the center of the region, structured with a dense network of roads, highways and railways and with a population of 835,053 inhabitants in 2011, making it the 7th-largest in Spain.

During the 20th century, Gijón developed as an industrial city in the steel and naval industries. However, due to the decline in manufacturing in these industries, in recent years Gijón is undergoing a transformation into an important tourist, university, commercial and R&D center. Gijón is the location of the Radiotelevisión del Principado de Asturias, the neighbourhood of Cimavilla, the Universidad Laboral de Gijón, the Revillagigedo Palace, and the adjoining Collegiate Church of San Juan Bautista.

Gijón is part of the statistical (not yet developed from an administrative standpoint) comarca of Gijón.

One theory based on some early medieval texts mention it as "Gigia", derived from the identical Greek and Latin term "gigias", meaning "giant", both of which refer to the Greek mythological giant Gigas. The medieval "Gigia" name, in turn, more specifically would refer to the ancient Roman wall built on the peninsula of the Cimavilla neighbourhood of Gijón. This wall was called the "Gegionem" by the Romans, and is itself a compound Latin term being either "geg-ionem", meaning "giant-ness/gigantic", "gegi-onem", meaning "concrete giant", or "gegio-nem" meaning "giant end". Presumably the use of the term meaning "giant" referred to either the pre-Germanic Astur peoples who inhabited the area being of large physical stature, or simply the largeness of the wall itself.

The name of the city might also come from the hypothetical Roman actual name of the place "Sessio" which may have turned into the word "Xixón" as the centuries went by. Then the Spanish word "Gijón", which has been also written during the Middle age as "Jijón" or even "Jixón", would be a Castilianization of the Asturian name. This theory is nowadays known as the most acceptable.

The first evidence of human presence in what is known nowadays as the municipality of Gijón is located on Monte Deva, where there exists a series of tumuli, and on Monte Areo, where there are some neolithic dolmens. These dolmens were discovered in 1990 and were supposedly built around 5000 BC.

The first noticed settlement (Noega) is located in Campa Torres. It has its origin between the 6th and 5th centuries BC. It was populated by Astures (Cilúrnigos) and later Romanized. Noega was progressively abandoned when the Roman wall in the peninsula of Cimavilla, called the Gegionem, was built.