Baliwag, officially the City of Baliwag (Filipino: Lungsod ng Baliwag, Tagalog: [bɐˈliʊag]; Kapampangan: Lakanbalen ning Baliwag/Siudad ning Baliwag), is a component city in the province of Bulacan, Philippines. According to the 2024 census, it has a population of 174,194 people.

The name Baliwag is derived from an old Kapampangan word meaning "untouched". The Kapampangan and Hispanicized spellings are used differently by locals: Baliwag refers to the entire city, while Baliuag refers to the city's downtown or poblacion (commonly called Baliuag Bayan or Baliuag Loob). The settlement was founded in 1732 by Augustinian friars and was incorporated by the Spanish governor-general on May 26, 1733. It was carved out of the town of Quingua (now Plaridel).

During the Spanish colonial period, Baliuag was predominantly agricultural, with rice farming serving as the principal source of livelihood. Orchards and tumanas produced fruits and vegetables that were sold in the public market. Commerce and industry also contributed significantly to the local economy. Baliuag became known for buntal hat weaving, silk weaving, the manufacture of cigar cases, piña fiber products, petates (mats), and sillas de bejuco (cane chairs), many of which were exported. The local market also expanded, and by the early 19th century, Baliuag was considered one of the most progressive and prosperous towns in Bulacan. The growth of the public market significantly transformed the town's economy.

Baliwag is the major commercial, transportation, entertainment, and educational center of northern Bulacan.

On July 22, 2022, Republic Act No. 11929 lapsed into law, converting the municipality into a component city and standardizing its name as the City of Baliwag. A plebiscite was held on December 17, 2022, in which 17,814 residents voted in favor of cityhood, while 5,702 voted against.

Fr. Joaquín Martínez de Zúñiga, OSA, a friar, in his "1803 Historia de las Islas Filipinas" wrote that the Convent or Parochial house of San Agustin, in Baliuag, is the best in the whole Archipelago and that no edifice in Manila can be compared to it in symmetry and beauty amid its towering belfry, having been a viewing point of the town's panorama. The frayle further stated that the Convent was a repository of priceless parish records that dated to the founding of Baliuag as a pueblo or parrochia by the OSA or Augustinians in 1733. But the first convent was erected at Barangay Santa Barbara, Baliuag before the Parokya was formally established at the now Plaza Naning, Poblacion.

Fr. Joaquín Martínez de Zúñiga arrived in the Philippines on August 3, 1786, and visited Baliuag on February 17, 1802, with Ignacio Maria de Álava y Sáenz de Navarrete. Their host was Baliuag's Parish Priest, Fray Esteban Diez Hidalgo. Fr. Diez served as the longest cura parroco of Baliuag from 1789, having built the church and convent from 1790 to 1801.

Spanish records "Apuntes históricos de la provincia augustiniana del Santísimo Nombre de Jesús de Filipinas" reveal that Fr. Juan de Albarran, OSA was assigned Parish Priest of Baliuag in 1733. The first baptism in Baliuag Church was ordered by Fr. Lector and Fr. Feliz Trillo, Provincial of the Province on June 7, 1733, while Baliuag was founded and began its de jure existence on May 26, 1733. The pueblo or town was created in the provincial Chapter on May 15, 1734, with the appointment of Fr. Manuel Bazeta/Baseta as first cura parroco.