Bad Kreuznach is a town in the Bad Kreuznach district in Rhineland-Palatinate, Germany. It is a spa town most well known for its medieval bridge dating from around 1300, the Alte Nahebrücke, which is one of the few remaining bridges in the world with buildings on it.

The town is located in the Nahe river wine region, renowned both nationally and internationally for its wines, especially from the Riesling, Silvaner and Müller-Thurgau grape varieties.

Bad Kreuznach does not lie within any Verbandsgemeinde, even though it is the seat of the Bad Kreuznach (Verbandsgemeinde). The town is the seat of several courts as well as federal and state authorities. Bad Kreuznach is also officially a große kreisangehörige Stadt ("large town belonging to a district"), meaning that it does not have the district-level powers that kreisfreie Städte ("district-free towns/cities") enjoy. It is, nonetheless, the district seat, and also the seat of the state chamber of commerce for Rhineland-Palatinate. It is classed as a middle centre with some functions of an upper centre, making it the administrative, cultural and economic hub of a region with more than 150,000 inhabitants.

The town of Bad Kreuznach is home to the following tourist attractions:

• The Alte Nahebrücke, a bridge that crosses the River Nahe in central Bad Kreuznach along the Walkplatz, dates from around 1300. It supports houses built from 1582 to 1612, and it is one of the few remaining bridges with buildings on it.
• The Pauluskirche (St. Paul's Church), where Karl Marx was married to Jenny von Westphalen on 19 June 1843.
• The Kurhaus (built in 1913) is a hotel and bath house. The baths which give the town its special designation contain the noble gas radon, with supposedly curative properties.
• The Dr-Faust-Haus (built in 1507) was the home of Johann Georg Faust, the alchemist on whom the Faust tale is said to be based.
• Two mosaics from a Roman villa (about AD 250) are displayed in an on-site museum, the Römerhalle. The tombstone of Tiberius Julius Abdes Pantera is also on view here.
• Bad Kreuznach's wine is well known.
• For 50 years Kreuznach was home to a United States Army base, Rose Barracks, including headquarters of the U.S. 8th Infantry Division, including the 8th Signal Battalion, and the 8th Intelligence Co., and later the U.S. 1st Armored Division, which closed down in May 2001