The first-generation Mercedes-Benz GL-Class (chassis code X164) unveiled at the 2006 North American International Auto Show in Detroit. Engineered on a stretched unibody architecture derived from the W164 M-Class, the GL was designed primarily for North American and global luxury buyers needing full seven-passenger capacity. Standard features included three-row seating with power-folding third row and AIRMATIC air suspension.

Engine offerings featured 3.0-liter V6 turbodiesels (GL 320 CDI, GL 350 BlueTEC) and 4.0-liter V8 turbodiesels (GL 420 CDI), alongside naturally aspirated 4.7-liter and 5.5-liter V8 gasoline engines (GL 450, GL 550). Power was dispatched through a 7G-TRONIC seven-speed automatic transmission and 4MATIC permanent all-wheel drive, with an optional Off-Road Pro Package adding low-range gearing and locking differentials. A 2009 facelift updated the front grille, LED daytime running lights, and interior trim.