Objectives: An overexpression of Tgf-β2 leads to calvarial hyperostosis and suture fusion in individuals with craniosynostosis. Inhibition of Tgf-β2 may help rescue fusing sutures and restore normal growth. The present study was designed to test this hypothesis. Design: Twenty-eight New Zealand White rabbits with delayed-onset coronal synostosis had radiopaque markers placed on either side of the coronal sutures at 10 days of age. The rabbits were randomly assigned to: (1) sham control rabbits (n = 10), (2) rabbits with control IgG (100 μg/suture) delivered in a collagen vehicle (n = 9), and (3) rabbits with Tgf-β2 neutralizing antibody (100 μg/suture) delivered in a collagen vehicle (n = 9). Longitudinal growth data were collected at 10, 25, 42, and 84 days of age. Sutures were harvested at 84 days of age for histomorphometry. Results: Radiographic analysis showed significantly greater ( P < .05) coronal suture marker separation, craniofacial length, cranial vault length, height, shape indices, cranial base length, and more lordotic cranial base angles in rabbits treated with anti-Tgf-β2 antibody than in controls at 42 and 84 days of age. Histologically, rabbits treated with anti-Tgf-β2 antibody at 84 days of age had patent and significantly ( P < .05) wider coronal sutures and greater sutural area compared to controls. Conclusions: These data support our hypothesis that antagonism of Tgf-β2 may rescue fusing coronal sutures and facilitate craniofacial growth in this rabbit model. These findings also suggest that cytokine therapy may have clinical significance in infants with progressive postgestational craniosynostosis.