Leipzig ( LYPE-sig, -⁠sikh, German: [ˈlaɪptsɪç] (listen); Upper Saxon: Leibz'sch) is the most populous city in the German state of Saxony. Leipzig's population of 624,689 inhabitants (1.1 million in the larger urban zone) as of 2022 places the city as Germany's eighth most populous, as well as the second most populous city in the area of the former East Germany after (East) Berlin. Together with Halle (Saale), the city forms the polycentric Leipzig-Halle Conurbation. Between the two cities (in Schkeuditz) lies Leipzig/Halle Airport.

Leipzig is located about 160 km (100 mi) southwest of Berlin, in the southernmost part of the North German Plain (the Leipzig Bay), at the confluence of the White Elster and its tributaries Pleiße and Parthe, that form an extensive inland delta in the city known as "Leipziger Gewässerknoten" (de), along which Europe's largest inner-city alluvial forest has developed. The city is surrounded by the Leipziger Neuseenland (Leipzig New Lakeland), a lake district consisting of several artificial lakes created from former lignite opencast mines. The name of the city and those of many of its boroughs are of Slavic origin.

Leipzig has been a trade city since at least the time of the Holy Roman Empire. The city sits at the intersection of the Via Regia and the Via Imperii, two important medieval trade routes. Leipzig's trade fair dates back to 1190. Between 1764 and 1945, the city was a center of publishing. After the Second World War and during the period of the German Democratic Republic (East Germany) Leipzig remained a major urban centre in East Germany, but its cultural and economic importance declined.

Events in Leipzig in 1989 played a significant role in precipitating the fall of communism in Central and Eastern Europe, mainly through demonstrations starting from St. Nicholas Church. The immediate effects of the reunification of Germany included the collapse of the local economy (which had come to depend on highly polluting heavy industry), severe unemployment, and urban blight. Starting around 2000, however, the decline was first arrested, then reversed, and since then Leipzig has seen many significant changes, including the restoration of major historical buildings, the demolition of derelict properties, and the development of new industries and a modern transport infrastructure.

Leipzig is home to one of the oldest universities in Europe (Leipzig University). It is the main seat of the German National Library (the second is Frankfurt), the seat of the German Music Archive, as well as of the German Federal Administrative Court. Leipzig was rated as the most livable city in Germany in 2013 by the GfK marketing research institution. Leipzig Zoo is one of the most modern zoos in Europe and ranks first in Germany (2013) and second in Europe (2015). Since Leipzig City Tunnel came into operation in 2013, Leipzig forms the centrepiece of the S-Bahn Mitteldeutschland public transit system. Leipzig was in 2020 listed as a "Sufficiency" level global city by the Globalization and World Cities Research Network, Germany's "Boomtown" and was the 2019 Academy of Urbanism European City of the Year.

Leipzig has long been a major centre for music, including classical and modern dark wave. The Thomanerchor (English: St. Thomas Choir of Leipzig), a boys' choir, was founded in 1212. The Leipzig Gewandhaus Orchestra, established in 1743, is one of the oldest symphony orchestras in the world. Johann Sebastian Bach and Felix Mendelssohn Bartholdy are two of several well-known composers who lived and worked in Leipzig. The University of Music and Theatre "Felix Mendelssohn Bartholdy" was founded in 1843. The Oper Leipzig, one of the most prominent opera houses in Germany, was founded in 1868. During a stay in Gohlis, which is now part of the city, Friedrich Schiller wrote his poem "Ode to Joy".