The Freightliner Argosy is a model line of cabover trucks that was produced by the American truck manufacturer Freightliner from the 1999 to 2020 model years. Developed as the replacement for the FLB cabover, the Argosy was a Class 8 truck, configured primarily for highway use. Competing against the International 9800, Kenworth K100E, and Peterbilt 362, the Argosy was the final Class 8 cabover marketed in North America, following the decline in use of the design in the United States and Canada.

After the 2006 model year, Freightliner shifted mass production of the model line entirely to export, ending sales of Class 8 COEs in North America. Sold nearly exclusively to South Africa, Australia, and New Zealand, the Argosy was produced through 2020. In North America, the model line remained available as a glider truck on a limited basis, ending in 2020.

Through its entire production, Freightliner assembled the Argosy in Cleveland, North Carolina. This facility produced vehicles for both North America and for export, as well as glider vehicles. In Australia and New Zealand, Freightliner replaced the Argosy with its Freightliner Cascadia conventional (bonneted) truck.

The Argosy made its debut in 1998 as the Freightliner Argosy Safety Concept Vehicle. Derived from the Freightliner Century Class conventional, the concept cabover truck shared major production components, including its doors, windshield, headlamps, and grille. Along with visual commonality, the Safety Concept Vehicle adopted telematics from the Century Class, facilitating electronic braking, messaging capability, daytime running lights, and traction control. In contrast to the production Argosy, the concept vehicle was fitted with a Mercedes-Benz OM457 12.0L I6 turbodiesel; it was fitted with 22.5-inch front wheels, with lower-profile 19.5-inch rear wheels.

Intended to preview a successor to the FLB-series cabover (introduced in 1987), the Argosy Safety Concept Vehicle was distinguished by a nearly flat interior floor (reducing the engine intrusion to only 3 inches high), outward-pivoting entrance steps, and a shorter vehicle length (allowing it to tow a trailer as long as 58 feet in the United States). While sales of COEs had declined to a 3% market share of the Class 8 truck segment for 1998, Freightliner had predicted that its new design would lead to a revival of the configuration.

Entering mass production in 1999, the Freightliner Argosy replaced both the FLB and FLA Class 8 COEs, becoming the third generation of tilting Freightliner cabovers. Adopting virtually the entire design of the 1998 concept vehicle, the Argosy combined the set-back and set-forward front axles of its predecessors with an axle placement directly below the driver.

Several cab configurations were introduced. Alongside a 63-inch (BBC) day-cab, sleeper cab lengths of 90 inches, 101 inches, and 110 inches were offered; sleeper cabs were offered in either a mid-roof or raised-roof configuration (110 inch length). The Argosy shared its 2-piece windshield with the Century Class; a 1-piece windshield (with 3 windshield wipers) was offered as an option.

Carrying over a distinguishing exterior feature from the concept vehicle, the production Argosy offered electrically-powered pivoting entrance steps. Offered on sleeper cabs (alongside a fuel tank fairing), the feature was standard on the driver side and optional on the passenger side. Coinciding with the lowered engine intrusion, the gear shifter was integrated into the dashboard console, allowing walk-in access to the sleeper cab. The Mercedes-Benz engine of the concept vehicle was not used for production, as the Argosy adopted the Cummins ISM, Cat C12, and Detroit Diesel Series 60 inline-6 diesels.