The Mercedes-Benz G-Class, sometimes colloquially called the G-Wagen (as an abbreviation of Geländewagen) is a four-wheel drive automobile manufactured by Magna Steyr (formerly Steyr-Daimler-Puch) in Austria and sold by Mercedes-Benz. Originally developed as a military off-roader, later more luxurious models were added to the line. In certain markets, it has been sold under the Puch name as Puch G until 2000.

The G-Wagen is characterised by its boxy styling and body-on-frame construction. It uses three fully locking differentials, one of the few passenger car vehicles to have such a feature.

Despite the introduction of an intended replacement, the unibody SUV Mercedes-Benz GL-Class in 2006, the G-Class is still in production and is one of the longest-produced vehicles in Daimler's history, with a span of 43 years. Only the Unimog surpasses it. In 2018, Mercedes-Benz launched a technically new second generation, still with only minor design changes.

The 400,000th unit was built on 4 December 2020