Rembang Regency (Indonesian: Kabupaten Rembang) is a regency (Indonesian: kabupaten) on the extreme northeast coast of Central Java Province, on the island of Java (bordering on the Java Sea) in Indonesia. The regency covers an area of 1,036.70 km on Java, and it had a population of 591,359 at the 2010 Census and 645,333 at the 2020 Census; the official estimate as of mid-2023 was 660,166, of whom 331,870 were males and 328,296 were females. Its administrative capital is the town of Rembang.

It is a lowland, with a maximum elevation of about 70 metres (230 ft) above sea level.

The Solo River flows through its inland section.

The regency is crossed by the North Coast Road, an inter-province main road on the island.

Rembang Regency is bordered by:

• North : Java Sea
• East : Tuban Regency in East Java Province
• South : Blora Regency
• West : Pati Regency

The regency is divided into fourteen districts (kecamatan), tabulated below with their areas and their populations at the 2010 Census and the 2020 Census, together with the official estimates as of mid-2023. The table also includes the locations of the district administrative centres, the number of administrative villages in each district (totaling 287 rural desa and 7 urban kelurahan - the latter all in Rembang town District), 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
33.17.01	Sumber	78.20	33,586	36,804	37,692	Sumber	18	59253
33.17.02	Bulu	101.10	25,649	28,019	28,669	Bulu	16	59255
33.17.03	Gunem	84.73	22,743	24,263	24,656	Gunem	16	59263
33.17.04	Sale	109.01	35,756	38,922	39,784	Sale	15	59265
33.17.05	Sarang	92.86	60,063	62,889	63,560	Kalipang	23	59274
33.17.06	Sedan	87.37	51,143	55,255	56,356	Sidorejo	21	59264
33.17.07	Pamotan	80.60	43,959	49,745	51,423	Pamotan	23	59261
33.17.08	Sulang	84.81	36,764	39,124	39,729	Sulang	21	59254
33.17.09	Kaliori	61.72	38,615	42,206	43,192	Tambakagung	23	59252
33.17.10	Rembang (town)	61.71	83,942	91,905	94,007	Leteh	34	59211 - 59219
33.17.11	Pancur	43.00	27,345	30,808	31,806	Pancur	23	59262
33.17.12	Kragan	67.08	58,232	65,499	67,589	Balongmulyo	27	59273
33.17.13	Sluke	38.28	26,620	29,512	30,326	Sluke	14	59272
33.17.14	Lasem	46.23	46,942	50,382	51,287	Soditan	20	59271
	Totals	1,036.70	591,359	645,333	660,166	Rembang	294

Note: (a) Rembang (town) District comprises 7 urban kelurahan (Gegunung Kulon, Kutoharjo, Leteh, Magersari, Pacar, Sidowayah and Tanjungsari) and 27 rural desa.

Rembang has a tropical monsoon climate (Am) with moderate to little rainfall from May to October and heavy rainfall from November to April.

During the colonial Dutch East Indies period, the area was known as Lasem.

The Han family of Lasem was a prominent Chinese immigrant family of colonial government bureaucrats and landlords in the area.

• Media related to Rembang Regency at Wikimedia Commons
• (in Indonesian) Official website

6°43′00″S 111°21′00″E / 6.71667°S 111.35000°E / -6.71667; 111.35000