Biała Podlaska (Polish: [ˈbjawa pɔdˈlaska] ^ⓘ; Latin: Alba Ducalis) is a city in the Lublin Voivodeship in eastern Poland with 56,498 inhabitants as of December 2021.^[update] It is the capital of Biała County, although the city is not part of the county (it constitutes a separate city county). The city lies on the Krzna river.

First recorded in the medieval period, Biała Podlaska is a former residential city of the once influential magnate Radziwiłł family, whose landmarks include a Palace and Park ensemble and Renaissance and Baroque churches. It is the location of one of the oldest high schools in Poland, whose student was the most prolific Polish 19th-century writer Józef Ignacy Kraszewski, the birthplace of virtuoso violinist George Bridgetower, and a former aircraft manufacturing centre. It was a place of Nazi German-perpetrated atrocities against Jews, Poles and Italians during the German occupation of Poland in World War II with over 4,000 victims. In 1975–1998, it was the capital of the Biała Podlaska Voivodeship.

The first historical document mentioning Biała Podlaska dates to 1481. In the beginning, Biała Podlaska belonged to the Illnicz family. The founder of the city may have been Piotr Janowicz, nicknamed "Biały" (Polish for "white"), who was the hetman of the Grand Duchy of Lithuania. Biała Podlaska was administratively part of the Podlaskie Voivodeship, and then the Brest Litovsk Voivodeship in the Grand Duchy of Lithuania (then in union with Poland).

In 1569, Biała Podlaska changed ownership; the new owners were the Radziwiłł family. Under their rule, Biała Podlaska had been growing for two and a half centuries. In 1622, Aleksander Ludwik Radziwiłł built the fortress and the castle. In 1628, Krzysztof Ciborowicz Wilski established Bialska Academy as a regional center of education (since 1633 it was a branch of the Jagiellonian University, then called Kraków Academy). It was one of the best schools in Poland in that time (about 1650–1700). During this time, many churches were erected, as was a hospital.

The prosperity period ended with the Swedish invasion in 1655. Then Biała Podlaska was attacked by Cossacks and Rákóczi armies. The town was significantly destroyed; however, thanks to Michał Kazimierz Radziwiłł and his wife Katarzyna Sobieska, it was rebuilt. In 1670, Michał Kazimierz Radziwiłł gives Biała Podlaska town rights and the coat of arms, which depicts archangel Michael standing on a dragon.

In 1720, Anna Katarzyna Radziwiłłowa began building the tower and the gate - both buildings exist to this day and are the most interesting remains of the castle and palace. In the 18th century, the city and the fortress were times destroyed many times in warfare and rebuilt. The last heir, Dominik Hieronim Radziwiłł, died on 11 November 1813 in France, as a colonel of the Polish army. The palace fell into ruin and was pulled down in 1883.

After the Third Partition of Poland in 1795, Biała Podlaska temporarily came under the rule of Austrian Habsburgs (Austrian partition of Poland). Following the Austro-Polish War of 1809, temporarily recovered by Poles, Biała Podlaska was part of the Polish Duchy of Warsaw. In 1815, the town became part of Congress Poland within the Russian Partition of Poland. At the end of the 19th century, Biała Podlaska was a large garrison town of the Imperial Russian Army. Near the intersection of Brzeska Street and Aleje Tysiclecia Avenue is a cemetery for soldiers killed during World War I.

In 1918, following World War I, Poland regained independence and the town was reunited with Poland. During the Second Polish Republic in the interwar period, Biała Podlaska was growing fast. The town was the seat of the Podlaska Wytwórnia Samolotów (PWS), an important aircraft factory.