The Chevrolet Cobalt SS comprises three sport compact versions of the Chevrolet Cobalt that were built on the General Motors Delta platform at Lordstown Assembly in Ohio, United States. The three versions included two forced induction inline-four Ecotec engines and a third naturally aspirated engine that was later called the Cobalt Sport. SS is an abbreviation of Super Sport, a historic moniker used by Chevrolet to denote high performance upgrades that meet certain criteria.

The Cobalt SS was GM's first foray into the tuner market, launching as a 205 hp (153 kW; 208 PS) supercharged 2.0 L coupe in late 2004, paired only with the F35 5-speed manual transmission of Opel. The following year, a naturally aspirated 1SS model equipped with GM's new 2.4 L 171 hp (128 kW; 173 PS) engine was added in both coupe and sedan body styles, including automatic and manual transmission options. Production of the supercharged coupe continued until 2007, and after a brief hiatus the SS relaunched in the second quarter of 2008 with a more efficient and powerful turbocharged 2.0 L engine producing 260 hp (194 kW; 264 PS) before all Cobalt production ended in 2010. (See timeline).

The Cobalt SS received generally positive reviews, particularly the turbocharged and supercharged versions. In a 2013 review, journalist Patrick George called it the best compact car ever made by General Motors, and a potential "future classic". At first release in 2004, the supercharged version was praised for its performance but drew criticism for its interior quality and exterior styling, both described as too reminiscent of its predecessor, the Cavalier. Reports surfaced in May 2009 that General Motors planned to eliminate the Cobalt SS as early as December 2009, but they proved to be untrue. Production continued but ordering options for late 2010 models were limited and production of all Cobalts ended in June 2009. The car was replaced by the Cruze, but a high performance version comparable to the Cobalt SS was never built and the Cruze ended production for the North American market in 2019.

The LSJ engine did not meet emissions requirements for the 2008 model year, and General Motors' contract with Eaton had expired. The non-supercharged 2.4 L Cobalt SS also lost its Super Sport designation for the 2008 model year and was renamed "Sport", leaving no SS in production. However, in fall 2007, a more powerful Cobalt SS was announced for the second quarter of 2008.[16] It would be equipped with the 2.0 L, turbocharged, direct injected, VVT, LNF Ecotec engine, making 260 hp (194 kW) at 5300 rpm and 260 lb⋅ft (353 N⋅m) at 2,000 rpm, remaining mated to the F35 5-speed manual transmission.[17] The engine had been introduced in a rear wheel drive application for the 2007 GM Kappa platform, which includes the Saturn Sky, Pontiac Solstice, and Opel GT.

Also new for the 2008 SS were SS-embroidered sport seats with suede-like UltraLux inserts, several new exterior colors, and wider 18-inch (460 mm) forged, split-spoke wheels with P225/40R18 Continental AG tires, styled similarly to those offered for the Chevrolet Corvette C6. The car's electronics were also new, and along with greater assist in poor traction conditions, a "no-lift-shift" feature was added which allows the driver to maintain turbocharger boost during shifts to a higher gear. During a no‑lift‑shift, the driver begins the shift normally by depressing the clutch, but the accelerator pedal is held wide open while the shift is completed. Also new was "launch control", which feathers the throttle at roughly 4,800 rpm until engagement of the clutch, allowing more consistent launches in competitive situations. To activate launch control, the driver presses twice on the traction control button which first turns off traction control, and then notifies the driver through the Driver's Information Center that Competitive Mode is active and launch control is ready for use. Turbocharged Cobalt owners have found that better times can be achieved while racing when the car is manually launched.[citation needed] These features help propel the car from 0 to 60 mph (97 km/h) in 5.5 seconds, and a quarter mile time of 13.9 seconds at 102.5 mph (165.0 km/h).

New for 2009 was the aforementioned four-door sedan option, as well as an optional "reconfigurable performance display" (RPD) for the coupe only. The $295 option replaced the boost gauge in the A‑pillar, and allows the driver to manipulate traction control, stability control, "shift points", and the engagement of Competition Mode, as well as information regarding the car's engine torque and horsepower, g‑force, boost, wideband air fuel ratio, barometric pressure, temperature, and battery voltage. For 2010, the RPD and a power sunroof were standard. The red/ebony and grey/ebony interior color options were also dropped, as was the turbocharged sedan.

A stage 1 kit which raises power to 290 hp (216 kW) and 340 lb⋅ft (461 N⋅m) was made available in October 2009 after several delays. The kit can be installed by the owner of the car, but final alteration of the vehicle's engine control unit must take place at a GM dealer.