The Akula class, Soviet designation Project 971 Shchuka-B (Russian: Щука-Б, lit. 'Pike-B', NATO reporting name Akula) is a series of fourth generation nuclear-powered attack submarines (SSNs) first deployed by the Soviet Navy in 1986. There are four sub-classes or flights of Shchuka-B, consisting of the original seven Project 971 boats (codenamed Akula I), commissioned between 1984 and 1990; six Project 971Is (Improved Akulas), commissioned between 1991 and 2009; one Project 971U (Akula II), commissioned in 1995; and one Project 971M (Akula III), commissioned in 2001. The Russians call all of the submarines Shchuka-B, regardless of modifications.

Some confusion may exist as the name Akula (Russian: Акула, meaning 'shark' in Russian) was used by the Soviets for a different class of submarines, the Project 941, which is known in the West as the Typhoon class. The Project 971 was named Shchuka-B by the Soviets but given the designation Akula by the West after the name of the lead ship, K-284.

According to defense analyst Norman Polmar, the launch of the first submarine in 1985, "shook everyone [in the West] up", as Western intelligence agencies had not expected the Soviet Union to produce such a boat for another ten years.

The Akula incorporates a double hull system composed of an inner pressure hull and an outer "light" hull. This allows more freedom in the design of the exterior hull shape, resulting in a submarine with more reserve buoyancy than its western analogs.

The distinctive "bulb" or "can" located on top of the Akula's rudder houses its towed sonar array when retracted. Most Akulas have the wake detection system (Russian: Система обнаружения кильватерного следа) (SOKS) hydrodynamic sensors, which detect changes in temperature and salinity. They are located on the leading edge of the sail, on the outer hull casing in front of the sail and on the bottom of the hull forward of the sail.

Akulas (excluding Nerpa) are armed with four 533 mm torpedo tubes which can use Type 53 torpedoes or the RPK-2, RPK-6 missile, and four 650 mm torpedo tubes which can use Type 65 torpedoes or the RPK-7 missile. These torpedo tubes are arranged in two rows of four tubes each. The external tubes are mounted outside the pressure hull in one row, above the torpedo tubes, and can only be reloaded in port or with the assistance of a submarine tender. The 650 mm tubes can be fitted with liners to use the 533 mm weaponry. The submarine is also able to use its torpedo tubes to deploy naval mines.

As with many Soviet/Russian craft, information on the status of the Akula-class submarines is sparse, at best. Information provided by sources varies widely.

Of the seven original Akulas, only three are known to still be in service. These boats are equipped with MGK-540 Skat-3 sonar system (NATO reporting name Shark Gill). The lead boat of the class, K-284 Akula, was decommissioned in 2001, apparently to help save money in the cash-strapped Russian Navy. K-322 Kashalot and K-480 Bars [currently Ak Bars] are in reserve. K-480 Bars was put into reserve in 1998, and was being dismantled in February 2010. Pantera returned to service in January 2008 after a comprehensive overhaul. All were retrofitted with the SOKS hydrodynamic sensors. All submarines before K-391 Bratsk have reactor coolant scoops that are similar to the ones of the Typhoon class SSBNs, long and tubular. Bratsk and subsequent submarines have reactor coolant scoops similar to the short ones on the Oscar IIs (the Typhoon, Akula and Oscar classes use the similar OK-650 reactor).