An apparatus for helping to protect an occupant of a vehicle includes a curtain airbag (CAB) having a packaged condition in which the CAB is rolled and/or folded to be installed along a roof rail in a vehicle. The CAB is configured to be inflated and deployed along a side structure of the vehicle structure. The apparatus includes an anti-twist structure for being positioned within the rolls and/or folds to inhibit relative twisting of the packaged CAB within the rolls and/or folds. The apparatus includes a CAB mount for extending about and supporting the packaged CAB in the vehicle. The CAB mount cooperates with the anti-twist structure to fix the position and orientation of the anti-twist structure, and thus the packaged CAB, relative to the vehicle.