This study uses U.S. field data to evaluate the effectiveness of rollover‐activated side curtain airbags in reducing fatalities in rollover crashes. Rollover‐activated side curtain airbags are designed to supplement seat belts in reducing risk of ejection and injury. Compared to traditional side‐impact airbags, the rollover‐activated side curtain airbags use more complex crash sensors and are designed to stay inflated longer to help secure occupants inside the vehicle in a rollover event. This technology, introduced in 2002, has since been widely used;​ about 30% of 2008 model year light vehicles on the road were equipped with rollover curtains as standard equipment. US fatal accident data from the Fatality Analysis Reporting System (FARS), the National Automotive Sampling System/General Estimates System (NASS/GES) databases, and state accident data files were examined for model years 2000‐2009. A matched‐pair comparison was made of the fatality rates of belted front outboard occupants involved in rollover crashes in vehicles equipped with and without rolloveractivated side curtain airbags as standard equipment. Effectiveness was estimated for “all belted” and “belted, non‐ejected” front outboard occupants. Results indicate rollover‐activated side curtain airbags in single‐vehicle accident rollovers are about 23% effective in reducing fatalities for all belted front outboard occupants, and about 20% effective in reducing fatalities for belted, non‐ejected front outboard occupants. Crash severity factors, such as high travel speed, are also shown to contribute to injury severity.