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 and stretching inland along the drainage area of the Siak River, as well as including other islands within the archipelago to its north-east. The land area covers 8,628.06 km 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 on the south coast of the island of the same name.

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 and 565,569 at the 2020 census; the official estimate as at mid 2023 was 662,521.

The eleven districts (kecamatan) currently forming the regency are listed below with their areas and their populations at the 2010 and 2020 censuses, together with the official estimates as at mid 2023. 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.

Kode Wilayah	Name of District (kecamatan)	Area in km	Pop'n census 2010	Pop'n census 2020	Pop'n estimate mid 2023	Admin centre	No. of villages	Post code
14.03.09	Mandau	372.50	219,264	152,258	166,828	Air Jamban	11	28783
14.03.13	Pinggir	811.45	78,404	62,098	77,346	Pinggir	10	28784
14.03.16	Bathin Solapan	855.62		91,586	115,542	Sebangar	13	28785
14.03.15	Talang Muandau	1,244.71		24,000	33,151	Beringin	9	28786
Sub-total	Southern (inland) group	3,284.28	297,668	329,942	392,867		43
14.03.03	Bukit Batu	446.28	30,129	21,771	22,896	Sungai Pakning	10	28761
14.03.12	Siak Kecil	858.90	18,709	24,186	28,263	Lubuk Muda	17	28771
14.03.14	Bandar Laksamana	1,372.71		15,842	19,014	Tenggayun	7	28762
Sub-total	Northern (coastal) group	2,677.89	48,838	61,799	70,173		34
14.03.10	Rupat	1,336.30	30,550	34,719	44,225	Batu Panjang	16	28781
14.03.11	Rupat Utara	368.68	13,020	14,117	17,013	Tanjung Medang	8	28782
14.03.01	Bengkalis	464.89	72,221	83,085	92,131	Bengkalis Kota	31	28711 - 28741
14.03.02	Bantan	446.29	36,039	41,907	46,112	Selat Baru	23	28763
Sub-total	Offshore islands group	2,616.16	151,830	173,828	199,481		89
	Total Regency	8,578.33	498,336	565,569	662,521	Bengkalis	155

Notes: (a) comprising 9 kelurahan (Air Jamban, Babussalam, Balik Alam, Batang Serosa, Duri Barat, Duri Timur, Gajah Sakti, Pematang Pudu and Makeruh (Talang Mandi)) and 2 desa.
(b) comprising 2 kelurahan (Balai Raja and Titian Antui) 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 (Sungai Pakning).
(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 (Batu Panjang, Pergam, Tanjung Kapal and Terkul) and 12 desa.
(h) comprising 3 kelurahan (Bengkalis Kota, Damon and Rimba Sekampung) and 28 desa.
(i) the northern part of Rupat Island. (j) the northern part of Bengkalis Island.

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 - Bukit Batu, Siak Kecil and Bandar Laksamana being on the Sumatran coast, while Mandau, Pinggir, Bathin Solapan and Talang Muandau are inland districts further south.