Lahat Regency is a regency of South Sumatra province, Indonesia. It originally included much of the southwestern part of the province, but on 21 June 2001 the town of Pagar Alam was removed from the regency to become an independent city, and on 2 January 2007 the western districts were split off to form the new Empat Lawang Regency. The reduced regency now covers a total area of 4,361.83 km² and had a population of 369,974 at the 2010 Census^[2] and 430,071 at the 2020 Census;^[3] the official estimate as at mid 2022 was 441,174 (comprising 225,428 males and 215,746 females).^[1] The city of Pagar Alam remains an enclave within the regency, but is administratively separate.

The administrative centre of Lahat regency is the town of Lahat.

This Regency as at 2010 was administratively composed of twenty-one districts (kecamatan). Since 2010 three additional districts have been created - Sukamerindu (from part of Pajar Bulan District), Lahat Selatan (from Lahat District) and Mulak Sebingkai (from Mulak Ulu District). Their areas (in km²) and their populations at the 2010^[2] and 2020^[3] Censuses are listed below, together with the official estimates as at mid 2022.^[1] The table also includes the locations of the district administrative centres, the number of administrative villages in each district (totaling 360 rural desa and 18 urban kelurahan - the latter - all but one - in Lahat District), and its post codes.

Notes: (a) The southwestern districts of Tanjung Sakti Pumu and Tanjung Sakti Pumi form an exclave of the regency, from which they are physically separated by the city (kota) of Pagar Alam.
(b) The 2010 population of Mulak Sebingkai District is included in the figure for Mulak Ulu District from which it was cut out.
(c) The 2010 population of Sukamerindu District is included in the figure for Pajar Bulan District, from which it was cut out. (d) comprising 17 kelurahan and 13 desa.
(e) The 2010 population of Lahat Selatan District is included in the figure for Lahat District, from which it was cut out. (f) including one kelurahan - the town of Lebuay Bandung.

In Lahat Regency, near Pagar Alam city, there are 1,027 artifacts which spread over 40 sites in 12 communities. The megalithic sites in Lahat Regency may be the second largest such sites in Indonesia after Sangiran (Central Java) for fossils.^[4]