Autologous fat tissue grafting (AFTG) has been successfully used in the treatment of different sclerotic conditions, including localized scleroderma. Patients with advanced systemic sclerosis (SSc)-related perioral thickening and mouth opening limitation are candidates for this therapeutic approach. AFTG of the lips was performed to improve mouth opening in patients with SSc. We enrolled in the study 20 female patients with diffuse SSc (median age 35 ± 15 years and 11 ± 10 years of disease duration). Two-milliliter fractions of autologous fat drawn from trochanteric or periumbilical areas were injected in eight different sites around the mouth. Baseline and after-treatment mouth opening changes were assessed by measuring interincisal distance and oral perimeter, while skin hardness was tested by digital durometer. Pre- and posttreatment modifications of microvascular architecture were assessed by counting capillaries in the inferior lip videocapillaroscopy (VC) images and by scoring the microvascular density (MVD) in anti-CD34/CD31 immunohistochemical (IH) stained perioral skin biopsy sections. Similarly, histological sections were examined to evaluate dermoepidermic junction (DEJ) modifications. Three months after treatment, both the interincisal distance and oral perimeter significantly increased (p < 0.001). At the same time, a significant skin neovascularization became evident, both considering the VC images (p < 0.001) and MVD scores in IH sections (p < 0.0001). Finally, some skin histological aspects also improved, as shown by the significant changes in DEJ flattening scores (p < 0.0001). The present study suggests that, in patients with SSc, AFTG can improve mouth opening and function, induce a neovascularization, and partially restore the skin structure.