Tanggamus Regency is a regency (kabupaten) of Lampung Province, Sumatra, Indonesia. It has an area of 4,654.96 km which consists of a land area of 2,855.46  km and a sea area of 1,799.5  km. It had a population of 534,595 at the 2010 Census and 640,275 at the 2020 Census; the official estimate as at mid 2023 was 662,542 (comprising 341,203 males and 320,339 females). The regency seat is the town of Kota Agung Pusat. The regency was created on 21 March 1997 from what were previously the western districts of South Lampung Regency, but districts in its eastern part split away on 29 October 2008 to form the new Pringsewu Regency. It lies in the southwest of the province, and surrounds Semangka Bay (Teluk Semangka) on its west, north and east coasts.

Tanggamus Regency is divided into twenty administrative districts (kecamatan), tabulated below with their total areas (including the sea 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 villages in each district (a total of 299 rural desa and 3 urban kelurahan, the latter all in Kota Agung District), and its post code.

Kode Wilayah	Name of District (kecamatan)	Total Area in km	Pop'n Census 2010	Pop'n Census 2020	Pop'n Estimate mid 2023	Admin centre	No. of villages	Post code
18.06.03	Wonosobo	209.63	34,102	41,281	42,830	Tanjung Kurung	28	35685
18.06.12	Semaka	170.90	34,287	39,498	40,390	Sukaraja	22	35386
18.06.25	Bandar Negeri Semuong	98.12	18,213	17,282	17,430	Sanggi	11	35686
18.06.01	Kota Agung	76.93	39,386	47,147	48,750	Kuripan	16	35381
18.06.17	Pematang Sawa	185.29	15,607	17,832	18,190	Way Nipah	14	35382
18.06.19	Kota Agung Timur (East Kota Agung)	73.33	17,645	21,581	22,460	Kagungan	12	35383
18.06.18	Kota Agung Barat (West Kota Agung)	101.30	20,749	22,839	23,040	Negara Batin	16	35384
18.06.04	Pulau Panggung (Panggung "Island")	437.21	31,906	40,310	42,340	Tekad	21	35678
18.06.15	Ulu Belu	323.08	38,718	43,803	44,550	Ngarip	16	35387
18.06.26	Air Naningan	186.35	27,051	31,237	31,960	Air Naningan	10	35679
18.06.02	Talang Padang	45.13	43,029	53,297	55,650	Talang Padang	20	35377
18.06.13	Sumberejo	56.77	31,146	36,056	36,920	Sumberejo	13	35374
18.06.20	Gisting	32.53	36,006	43,049	44,490	Kuta Dalom	9	35378
18.06.21	Gunung Alip	25.68	17,263	22,151	23,370	Banjar Negeri	12	35379
18.06.11	Pugung	232.40	51,832	66,185	69,720	Rantau Tijang	27	35675
18.06.27	Bulok	51.68	19,532	24,139	25,190	Sukamara	10	35682
18.06.09	Cukuh Balak	133.76	21,087	24,846	25,570	Putih Doh	20	35683
18.06.17	Klumbayan	121.09	10,746	12,236	12,470	Napal	8	35388
18.06.24	Limau	240.61	17,032	21,665	22,800	Kuripan	11	35613
18.06.28	Kelumbayan Barat (West Kelumbayan)	53.67	11,276	13,841	14,410	Sidoharjo	6	35389
	Totals	4,654.96	536,613	640,275	662,542	Kota Agung Pusat	302

Notes: (a) includes the 3 kelurahan of Baros, Kuripan and Pasar Madang. (b) includes the substantial island of Pulau Tabuan in the southern entrance to Semangka Bay, and three small offshore islands (Pulau Batucentigi, Pulau Batuputih and Pulau Karangputih).
(c) includes 25 small offshore islands. (d) includes the small offshore island of Pulau Batukerbau.
The Area consists of 2,855.46 km Land Area and 1,799.50 km Sea Area.

In the winter of 2009/2010, the regency suffered from flooding, which saw some 80 percent of the forest in Tanggamus severely damaged. Landslides occurred in the district of Semaka and the flooding drowned several elephants including one within the protected Bukit Barisan Selatan National Park and another at the Way Kerap dam in Tanggamus.

Bukit Barisan Selatan National Park is a National Park in the area. A Tropical Forest World Heritage Site, Bukit Barisan has a total area of 3,568 km2.

The district has an area of 4,654.96 square km with a population density of around 140 people/square km, and was inaugurated on 3 January 1997, based on Law Number 2 of 1997.

• Kiluan Bay
• Gigi Hiu Beach
• Tanggamus Mountain
• Sawmiil Beach
• Way Lalaan Waterfall
• Jarum Lebuay Waterfall
• Batutegi Dam
• Lembah Pelangi Waterfall

5°23′06″S 104°37′25″E / 5.3851°S 104.6235°E / -5.3851; 104.6235