Hello Kathy,
I'm sure your FJ Cruiser already has some sort of roof rack which will be needed. So yes it will most likely fit your FJ Cruiser. The Smittybilt Retractable Awning part number S/B2784 is designed to fit applications where the surface to mount is at most 8.2 feet long (8'2.6"), and at least somewhere around 6ft.
It comes with L-Brackets and U-Bolt type brackets where you can use both together or a special configuration. You can also use specialty aftermarket brackets (these mostly depend on the roof rack you already have). The brackets install to the awning through channels, making it very adjustable to your mounting needs.
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