Busko-Zdrój ([ˈbuskɔ ˈzdrui̯] ^ⓘ) is a spa town in Świętokrzyskie Voivodeship, southern Poland. It is the capital of Busko County. As of December 2021, it has a population of 15,310.

The origin of Busko goes back to the 12th century, when a group of shepherds settled around St. Leonard's church. In 1185, Knight Dersław, the owner of Busko and its surroundings, brought Norbertine nuns, whom in his will he inscribed i.a. the village of Busko. Dersław was probably killed in the Battle of Chmielnik in 1241 (see: Mongol invasion of Poland). In 1251, it received a revenue privilege from King Bolesław V the Chaste allowing the convent to use the salt water. This is the first record of the use of Busko's mineral waters.

In 1287, Busko was granted civic rights by King Leszek II the Black. The advantageous location of the town on trade routes led King Władysław Jagiełło to grant local burghers the right to have a weekly market and two fairs a year beginning in 1412. The 15th and 16th centuries were considered^{[by whom?]} the "heyday" of the town. It was famous for its trade and cloth production.

Busko is located in the south part of the Świętokrzyskie voivodeship, 50 km (31 mi) from Kielce and 80 km (50 mi) from Kraków. The city is in the part of the Świetokrzyskie voivodeship called Ponidzie, whose name came from the river Nida.

According to information from 2002, the area of the Busko–Zdrój is 12.28 square kilometres (4.7 sq mi).

Busko-Zdrój composes 4.95% of the surface area of the parish.

Detailed data as of 31 December 2021:

Busko's climate is low-lying and continental. This weather is typical about 39% of the days of the year. The number of 'hot and scorching' days -13%, 'very cold' – under 1.5%. The average year-round temperature is 7.8 °C (46.0 °F). The minimum average temperature of the year is −8.2 °C (17.2 °F). The maximum average temperature of the year is 23.4 °C (74.1 °F). In Busko, there are almost 1151 hours of sunshine per year. The average humidity is between 71% and 80%.