OKBM Afrikantov (full name: OAO I. I. Afrikantov OKB Mechanical Engineering, Russian: Опытное конструкторское бюро машиностроения им. И. И. Африкантова, lit. 'I. I. Afrikantov Experimental Design Bureau of Mechanical Engineering') is a nuclear engineering company located in Nizhny Novgorod, Russia. It is a subsidiary of Rosatom.

The company is named after Igor Afrikantov, and is best known as the main designer for the Soviet Union's and Russia's flagship nuclear propulsion projects, including reactors for nuclear submarines, nuclear-powered icebreakers, and the floating nuclear power plant project. It also designs fast breeder reactors.

Nearly 4,000 people work for OKBM, including more than 1,600 design engineers, production engineers and test engineers. The company's employees include one Academician of the Russian Academy of Science, 20 Doctors of Engineering Science and 92 Candidates of Engineering Science. Throughout the years in action, OKBM has made a great contribution to the development of the Russian nuclear industry, the energy sector and the fleet.

The company was founded in 1945, by the decree of the Council of People's Commissars of the USSR dated December 27, 1945, a Special Design Bureau (OKB) was established on the basis of the Nizhny Novgorod Machine-building Plant to create equipment for the nuclear industry.

In 1960, the OKB was awarded the highest state award, the Order of Lenin, for its participation in the creation of the power plant of the first nuclear icebreaker: Lenin.

In 1985, the OKB was awarded the Order of the October Revolution for its significant contribution to the development of nuclear technology.

In 1998 the enterprise was named after its former chief designer and director I. I. Afrikantov.

In 2004, by a decree of the Government of the Russian Federation, OKBM was granted the status of a Federal Scientific and Production Center.