Cranioplasty in facial feminization surgery (FFS) contours the frontal bone to achieve an improved feminine appearance of the forehead. The surgery was first described in 1986 by Whitaker et al1 and then in 1987 by Ousterhout.2 Since then, multiple articles have focused on the technique and the clinical outcomes of the surgery specific to FFS.3,4 In general, the frontal bone is approached via a coronal incision to contour frontal bossing and the orbital rims. Variable techniques to address frontal bossing are reported, including using a burr alone, onlay implants, and osteoplastic flap setback. One critical component of frontal cranioplasty is the ability to safely and effectively reduce bony prominence overlying the frontal sinus/absent frontal sinus. Previously, the amount of bone reduction was based on the external appearance with or without imaging. Interestingly, frontal sinus transillumination for estimation of frontal sinus configuration in osteoplastic flap surgery is described in the context of rhinologic disease but not FFS.5,6 Here, we describe the use of frontal sinus transillumination in cranioplasty during FFS (Video 1).