The Regentenbau (German for "regent's building") is a concert hall in the town Bad Kissingen in Bavaria, Germany.
The concert hall was built from 1911 to 1913 in a neo-baroque style according to the plans of the architect Max Littmann. Prince regent Luitpold of Bavaria commissioned the construction of the Regentenbau. The building was inauguratet by his son and successor Ludwig III of Bavaria on 15 and 16 May 1913. The owner is the state of Bavaria. The Regentenbau is under monument protection and is registered under the number D-6-72-114-38.
Situated between the Kurgarten (spa garden) and the river Fränkische Saale, the Regentenbau completed the spa area of Bad Kissingen. It was the conclusion of the comprehensive building contract in the royal spa, which Luitpold of Bavaria had given in 1905 to Max Littmann as "special commissioner for the state's new buildings in the royal spa garden". This order, for which the Bavarian government released funding in 1910, included also the construction of the Wandelhalle (promenade hall) and the renovation and structural integration of the older Arkadenbau of Friedrich von Gärtner, a 200-meter-long arcade building from 1838 with its hall Conversationssaal (today Rossini-Saal), to the Regentenbau.
From the opening until 1918 the Vienna Symphony as the saisonal spa orchestra performed its evening concerts at the Regentenbau. The Munich Philharmonic followed from 1919 to 1942. Then musical life ended because of the Second World War. After the war the Regentenbau was occupied by the American troops for two years. Musical life startet again in 1950 with the Hofer Symphoniker (until 1979). Since 1986 the Regentenbau is the main location of the festival Kissinger Sommer.