Lamongan Regency (Javanese: ꦏꦧꦸꦥꦠꦺꦤ꧀ꦭꦩꦺꦴꦔꦤ꧀) is a regency (kabupaten) of the East Java Province of Indonesia. It has a total land area of approximately 1,812.8 km (699.9 sq mi) or + 3.78% of the area of East Java Province. With a length of 47 km (29 mi) along the coastline (comprising Paciran and Brondong Districts), the sea area of Lamongan Regency is about 902.4 km (348.4 sq mi), if calculated to a distance of 12 miles (19 km) across the ocean surface. At the 2010 census it had a population of 1,179,059; the 2020 Census produced a total of 1,379,628 and the official estimate as at mid-2023 was 1,385,835 (comprising 694,803 males and 691,032 females). The regency seat is the town of Lamongan, situated on the Solo River which passes from west to east through the regency, effectively dividing it in two.

There are three main geographic divisions. In the far south of the regency (Sukorame, Bluluk, Ngimbang, Sambeng, Mantup and Modo Districts), and also in the northern coastal area (Brondong, Paciran and Solokuro Districts) are limestone mountains with land of medium fertility. Between the coastal uplands and the Solo River, much of the region consists of 'bonorowo' wetlands prone to periodic flooding (chiefly Glagah, Karangbinangun, Turi, Kalitengah, Karanggeneng, Laren, Maduran and Sekaran Districts). The remaining areas close to and south of the Solo River comprise lowlands of limited fertility (Kembangbahu, Sugio, Kedungpring, Babat, Pucuk, Sukadadi, Lamongan, Tikung, Sarirejo and Deket Districts).

Lamongan Regency is bordered by:

• Northern side  : Java Sea
• Southern side  : Mojokerto Regency and Jombang Regency
• Eastern side  : Gresik Regency
• Western side  : Tuban Regency and Bojonegoro Regency

The economy is mainly supported by agriculture, fishery, and commerce, especially the home industry.

Lamongan Regency consists of twenty-seven districts (kecamatan), tabulated below with their areas and population totals from 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 462 rural desa and 12 urban kelurahan), and their postal codes.

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 codes
35.24.01	Sukorame	41.47	20,126	21,671	21,639	Sukorame	9	62276
35.24.02	Bluluk	54.15	21,429	23,106	23,097	Bluluk	9	62274
35.24.04	Ngimbang	114.33	43,678	49,008	49,497	Sendangrejo	19	62273
35.24.11	Sambeng	195.44	47,998	52,727	52,824	Ardirejo	22	62284
35.24.16	Mantup	93.07	42,750	46,795	46,906	Mantup	15	62283
35.24.19	Kembangbahu	63.84	46,032	50,154	50,613	Kembangbahu	18	62282
35.24.12	Sugio	91.29	54,478	63,069	63,255	Sugio	21	62256
35.24.06	Kedungpring	84.43	50,313	62,642	62,045	Kedungpring	23	62272
35.24.03	Modo	77.80	44,988	51,247	51,197	Mojorejo	17	62275
35.24.05	Babat	62.95	76,178	92,301	91,285	Bedahan	23	62271
35.24.13	Pucuk	44.84	39,053	49,785	48,869	Pucuk	17	62257
35.24.17	Sukodadi	52.32	50,682	57,823	59,592	Sukodadi	20	62253
35.24.22	Lamongan (town)	40.38	65,083	69,517	71,080	Lamongan	20	62211 - 62218
35.24.23	Tikung	52.99	41,483	45,983	47,622	Bakalanpule	13	62280
35.24.27	Sarirejo	47.39	22,503	24,958	25,597	Dermolemahbang	9	62281`
35.24.25	Deket	50.05	41,045	44,030	44,057	Deketwetan	17	62291
35.24.26	Glagah	40.52	35,014	41,539	41,347	Glagah	29	62292
35.24.24	Karangbinangun	52.88	33,285	40,445	40,943	Sambopinggir	21	62293
35.24.21	Turi	58.69	47,711	54,273	55,282	Sukoanyar	19	62252
35.24.20	Kalitengah	43.35	30,094	35,867	36,549	Dibee	20	62255
35.24.18	Karanggeneng	51.32	36,609	43,702	44,216	Karanggeneng	18	62254
35.24.09	Sekaran	49.65	33,443	48,091	44,434	Bulutengger	21	62260
35.24.10	Maduran	30.15	26,288	36,474	34,162	Maduran	17	62261
35.24.08	Laren	95.00	36,492	51,399	51,091	Gampangsejati	20	62262
35.24.15	Solokuro	101.02	39,530	48,057	49,904	Payaman	10	62265
35.24.14	Paciran	47.89	90,700	97,803	99,986	Paciran	17	62264
35.24.07	Brondong	74.59	62,074	77,023	78,696	Brondong	10	62263
	Totals	1,812.80	1,179,059	1,379,628	1,385,835	Lamongan	474

Notes: (a) includes 2 kelurahan (Babat and Banaran). (b) comprises 8 kelurahan (Banjarmendalan, Jetis, Sidoharjo, Sidokumpul, Sukomulyo, Sukorejo, Tlogoanyar and Tumenggungan) and 12 desa.
(c) including one kelurahan (Blimbing). (d) including one kelurahan (Brondong).

Lamongan has a tropical savanna climate (Aw) with moderate to little rainfall from May to November and heavy rainfall from December to April. The following climate data is for the town of Lamongan.

On 29 April 2013, Paciran Port (Class I ASDP) was officially opened to support the overloaded Tanjung Perak Port.

Persela is a football team based in Lamongan. Former Persela Lamongan goalkeeper Choirul Huda was from Lamongan.