Metz (/ˈmɛts/ METS, French: [mɛs] ^ⓘ, Latin: Divodurum Mediomatricorum, then Mettis) is a city in northeast France located at the confluence of the Moselle and the Seille rivers. Metz is the prefecture of the Moselle department and the seat of the parliament of the Grand Est region. Located near the tripoint along the junction of France, Germany and Luxembourg, the city forms a central part of the European Greater Region and the SaarLorLux euroregion.

Metz has a rich 3,000-year history, having variously been a Celtic oppidum, an important Gallo-Roman city, the Merovingian capital of Austrasia, the birthplace of the Carolingian dynasty, a cradle of the Gregorian chant, and one of the oldest republics in Europe. The city has been steeped in French culture, but has been strongly influenced by German culture due to its location and history.

Because of its historical, cultural and architectural background, Metz has been submitted on France's UNESCO World Heritage Tentative List. The city features noteworthy buildings such as the Gothic Saint-Stephen Cathedral with its largest expanse of stained-glass windows in the world, the Basilica of Saint-Pierre-aux-Nonnains being the oldest church in France, its Imperial Station Palace displaying the apartment of the German Kaiser, or its Opera House, the oldest one working in France. Metz is home to some world-class venues including the Arsenal Concert Hall and the Centre Pompidou-Metz museum.

A basin of urban ecology, Metz gained its nickname of The Green City (French: La Ville Verte), as it has extensive open grounds and public gardens. The historic city centre is one of the largest commercial pedestrian areas in France.

A historic garrison town, Metz is the economic heart of the Lorraine region, specialising in information technology and automotive industries. Metz is home to the University of Lorraine, Georgia Tech Europe, and a centre for applied research and development in the materials sector, notably in metallurgy and metallography, the heritage of the Lorraine region's past in the iron and steel industry.

In ancient times, the town was known as "city of Mediomatrici", being inhabited by the tribe of the same name. After its integration into the Roman Empire, the city was called Divodurum Mediomatricum, meaning Holy Village or Holy Fortress of the Mediomatrici, then it was known as Mediomatrix. During the 5th century AD, the name evolved to "Mettis", which gave rise to the current spelling, Metz, but also spellings such as Mès, which are no longer used, but reflect its actual pronunciation in French (like "mess").

Metz has a recorded history dating back over 2,000 years. Before the conquest of Gaul by Julius Caesar in 52 BC, it was the oppidum of the Celtic Mediomatrici tribe. Integrated into the Roman Empire, Metz became quickly one of the principal towns of Gaul with a population of 40,000, until the barbarian depredations and its transfer to the Franks about the end of the 5th century. Between the 6th and 8th centuries, the city was the residence of the Merovingian kings of Austrasia. After the Treaty of Verdun in 843, Metz became the capital of the Kingdom of Lotharingia and was ultimately integrated into the Holy Roman Empire, being granted semi-independent status. During the 12th century, Metz became a republic and the Republic of Metz stood until the 15th century.

With the signature of the Treaty of Chambord in 1552, Metz passed into the hands of the Kings of France. As the German Protestant Princes who traded Metz (alongside Toul and Verdun) for the promise of French military assistance, had no authority to cede territory of the Holy Roman Empire, the change of jurisdiction was not recognised by the Holy Roman Empire until the Treaty of Westphalia in 1648. Under French rule, Metz was selected as capital of the Three Bishoprics and became a strategic fortified town. With creation of the departments by the Estates-General of 1789, Metz was chosen as capital of the Department of Moselle.