Petukhovskoye (Russian: Петуховское), also known as Petukhovo, is an alkaline lake in Klyuchevsky District, Altai Krai, Russian Federation.

The lake is located at the western edge of the Krai, only 7 kilometers (4.3 mi) east of the Russia-Kazakhstan border. The nearest inhabited place is Severka 5 kilometers (3.1 mi) to the east of the eastern end. Klyuchi, the district capital, lies 13 kilometers (8.1 mi) to the north.

Located in the Kulunda Plain, Petukhovskoye has an elongated shape, stretching roughly from northeast to southwest for approximately 3 kilometers (1.9 mi). The lake dries during summers of drought, becoming a salt pan. Salt was mined in the lake in the past. The indicator minerals in the sediments of the lake are pyrite, disordered Ca-smectites, and dolomite, the latter being markedly predominant, especially in the lower part of the sediment section. The water has a mineralization of 24.3 grams per liter (3.90 oz/imp gal) and a pH of 9.8.

Metagenomic analyses of lake samples collected in July 2016 indicate the presence of archaea belonging to the Lokiarchaeota group (MAG: Ca. Lokiarchaeota archaeon isolate CSSed165cm_327R1) among other microbes.

Lake Gornostalevo lies 17 kilometers (11 mi) to the south and Kurichye 21 kilometers (13 mi) to the ENE. 24 kilometers (15 mi) to the northeast lies lake Petukhovo, near Petukhi.

The lake is surrounded by forest steppe. There are also sand dunes.

• List of lakes of Russia

• Biota of hyperhaline lakes of the south of Western Siberia