Bengkalis Regency is a regency of Indonesia in Riau Province. The regency was originally established in 1956 and then included most of the northern part of the province, but on 4 October 1999 it was divided up, with most of the territory being split off to form the new Rokan Hilir Regency, Siak Regency and the city of Dumai. On 19 December 2008 a further five districts were removed to create the new Meranti Islands Regency, leaving eight districts (or kecamatan) in the Bengkalis Regency. These eight districts has increased since 2010 to eleven by the splitting of existing districts on the Sumatran mainland.

Bengkalis Regency produces natural resources, particularly petroleum, rubber, and coconut. The southern part of this regency contains a large part of the Bukit Batu Biosphere Reserve.

Bengkalis Regency comprises the whole of Bengkalis Island and Rupat Island, which are located in the Straits of Malacca, together with a wide swathe of the eastern coastal area of Sumatra Island as well as other islands within the archipelago to its north-east. The land area covers 8,628.05 km² and it borders on the Malacca Straits to the north, on Siak Regency to the south, on the Meranti Islands Regency to the southeast, and on Dumai City, Rokan Hilir Regency and Rokan Hulu Regency to the west. The administrative centre is the town of Bengkalis.

The Bengkalis Strait separates Bengkalis Island from Sumatra as well as from Padang Island and Tebing Tinggi Island.

Following the splitting in 2008 of the regency to create a new Meranti Islands Regency, the residual area of Bengkalis Regency had a population of 498,336 at the 2010 census^[2] and 565,569 at the 2020 census;^[3] the official estimate as at mid 2022 was 582,973 (comprising 298,518 males and 284,455 females).^[1]

The eleven districts (kecamatan) currently forming the regency are listed below with their areas and their populations at the 2010^[2] and 2020 censuses,^[3] together with the official estimates as at mid 2022.^[1] The table also includes the locations of the district administrative centres, the number of administrative villages in each district (a total of 136 rural desa and 19 urban kelurahan), and its post code.

Notes: (a) comprising 9 kelurahan and 2 desa. (b) comprising 2 kelurahan and 8 desa. (c) the 2010 population of the new Bathin Solapan District is included in the figure for Mandau District, from which it was cut out.
(d) the 2010 population of the new Talang Muandau District is included in the figure for Pinggir District, from which it was cut out. (e) including one kelurahan.
(f) the 2010 population of the new Bandar Laksamana District is included in the figure for Bukit Batu District, from which it was cut out. (g) comprising 4 kelurahan and 12 desa. (h) comprising 3 kelurahan and 28 desa.

Bengkalis Island comprises Bengkalis District and Bantan District, while Rupat Island comprises Rupat District and Rupat Utara (North Rupat) District. The remaining seven districts lie on Sumatra Island.