Geisenheim (German pronunciation: [ˈɡaɪzn̩ˌhaɪm] ^ⓘ) is a town in the Rheingau-Taunus-Kreis in the Regierungsbezirk of Darmstadt in Hessen, Germany, and is known as Weinstadt (“Wine Town”), Schulstadt (“School Town”), Domstadt (“Cathedral Town”) and Lindenstadt (“Linden Tree Town”).

Geisenheim lies on the Rhine’s right bank between Wiesbaden and Rüdesheim, 3 km away to the west. Mainz lies 21 km away to the east.

Geisenheim borders in the north on the town of Lorch, in the east on the town of Oestrich-Winkel, in the south on the towns of Ingelheim and Bingen (both in Mainz-Bingen in Rhineland-Palatinate) and in the west on the town of Rüdesheim.

The town of Geisenheim is divided into four Stadtteile: the main town (also called Geisenheim), Johannisberg (Grund, Berg, Schloßheide), Marienthal and Stephanshausen.

Johannisberg might well be the best known of Geisenheim’s constituent communities, being the birthplace of Spätlese (more precisely, the systematic production of Auslesen), and being known worldwide for its appellation.

At Schloss Johannisberg, a statue today still recalls the unknown Spätlesereiter (“Late Harvest Rider”). Through the vineyards here, below the Schloss runs the 50th parallel of north latitude. Prince Klemens Wenzel von Metternich acquired the Schloss domain in 1816 after the Congress of Vienna from its former holder, Emperor Franz I as a gift.

Marienthal gets its name from the nearby Marienthal Monastery. The monastery is well known for its Marienwallfahrt (pilgrimage), and here was also the world's first monastery printing shop.

Geisenheim has an oceanic climate (Köppen: Cfb), although slightly more extreme than coastal cities, the city is still strongly influenced by the west winds due to flat relief and the presence of inland seas. The relatively mild climate makes the cidae one of the leading regions of quality wines, as well as elsewhere in Rheingau (covered with hills that protect from the cold in the Rhine valley).