Sigi Regency is a regency of Central Sulawesi, Indonesia. It was created on 21 July 2008 by splitting off the southern districts from Donggala Regency. It lies upstream on the Palu River, and immediately south of Palu city, the provincial capital. The regency is almost landlocked; it has a small coastline between Palu city and the western part of Donggala regency. It covers an area of 5,196.02 km and had a population of 215,030 at the 2010 Census and 239,421 at the 2020 Census; the official estimate as at mid 2023 was 266,656 (comprising 136,510 males and 130,140 females). The principal town lies at Sigi Biromaru.

Sigi Regency was one of the areas in northwest Sulawesi most affected by the 2018 earthquake and tsunami in Sulawesi. Dozens of people were reported to have been killed by the earthquake and there were reports of "massive liquification" which caused homes to be swept away.

Following religious conflicts in the neighbouring Poso Regency, the Indonesia government mounted Operation Tinombala in early 2016 to combat local terrorist activities carried out by the East Indonesia Mujahiddin (Mujahiddin Indonesian Timur, or MIT) in the province. In late November 2020, there were indications that the conflict had spread into Sigi Regency when four residents of remote Lembantongoa village were killed in an apparent terrorist attack attributed to MIT. Indonesia's senior Coordinating Political, Legal and Security Minister Mahfud MD issued a statement saying that the government was committed to tracking down those responsible for the murders and the accompanying destruction.

The Sigi Regency was divided at 2010 and at 2020 into fifteen districts (kecamatan), but on 14 September 2020 a sixteenth district (Sigi Kota) was formed from parts of Sigi Biromaru (7 desa), Dolo (2 desa) and Palolo (1 desa) Districts. The districts are tabulated below with their areas and their populations at the 2010 Census and 2020 Census, together with the official estimates as at mid 2023. The table also includes the locations of the district administrative centres, and the numbers of villages (all rated as rural desa) in each district.

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 desa
72.10.07	Pipikoro	956.13	7,817	8,720	8,615	Peana	19
72.10.06	Kulawi Selatan (South Kulawi)	418.12	8,473	9,440	9,772	Lawua	12
72.10.05	Kulawi	1,053.56	14,172	15,810	16,305	Bolapopo	16
72.10.04	Lindu	552.03	4,690	5,250	5,557	Tomado	5
72.10.03	Nokilalaki	75.19	5,626	6,260	5,731	Kamarora	5
72.10.02	Palolo	581.48	27,385	30,440	29,983	Makmur	21
73.10.08	Gumbasa	176.49	11,682	13,010	13,578	Pakuli	7
72.10.10	Tanambulava	56.33	7,866	8,770	9,895	Sibalaya Utara	5
72.10.09	Dolo Selatan (South Dolo)	584.71	14,448	16,080	17,284	Baluase	12
72.10.11	Dolo Barat (West Dolo)	112.18	12,576	14,010	15,183	Kalele	12
72.10.12	Dolo	21.79	20,591	22,930	23,206	Kota Pulu	9
72.10.01	Sigi Biromaru	175.29	42,857	47,710	48,775	Mpanau	10
72.10.14	Marawola	38.65	20,991	23,360	30,068	Binangga	11
72.10.15	Marawola Barat (West Marawola)	150.51	6,382	7,100	5,789	Dombu	12
72.10.13	Kinovaro	70.38	9,474	10,540	10,794	Porame	10
72.10.16	Sigi Kota (Sigi Town)	173.10			16,121	Bora	10
	Totals	5,196.02	215,030	239,421	266,656	Sigi Biromaru	177

Note (a) the population of the new Sigi Kota District in 2010 and 2020 is included in the figures for Sigi Biromaru, Dolo and Palolo Districts, from parts of which it was created on 14 September 2020.

1°23′06″S 119°58′01″E / 1.38500°S 119.96694°E / -1.38500; 119.96694