The Landesmuseum Mainz is a museum in Mainz dedicated to the history and art of the city and the state of Rhineland-Palatinate. It is one of the oldest museums in Germany. The core of the collection dates back to 1803 on the initiative of Napoleon Bonaparte himself, who commissioned Jean-Antoine Chaptal to create a municipal collection in Mainz, having 36 paintings transferred to the city to create an art gallery.

Today, the museum's collection is highly diversified internally and spans a span of time from prehistoric times to the present day. Among the oldest pieces in the collection is the "Venus vom Linsenberg", a paleolithic female statuette (dated around 23,000 BC). A further similar figure has survived only in fragments: these two sculptures can be considered the oldest surviving works of art in the Mainz area. There are also finds from Celtic tombs, such as the so-called "Glashund von Wallertheim" dating back to the third century BC, a figure made of blue glass decorated with white and yellow glass threads. There are also Roman finds in glass, ceramic and bronze, objects of art and everyday use and wall paintings. The collection of stone finds from the Roman era includes over 2000 individual pieces. It includes military and civil tombstones, altars, sarcophagi, sculptures and architectural parts.

The medieval section includes paintings, sculptures and architectural ornaments from medieval buildings, often lost as they were badly damaged. The Renaissance section includes important masterpieces from the most important European Renaissance schools. The collection of 19th century paintings includes numerous works, mainly by regional and national artists. There is the richest collection of works by Max Slevogt, representative of the so-called "German Impressionism". The museum also houses the largest graphic collection in Rhineland-Palatinate, with 45,000 graphic works, including sheets by Edgar Degas, Paul Signac, Alfred Sisley and Pablo Picasso.