Background: The extended survival of patients with early glottic cancer has heightened concerns about the long-term side effects of radiation therapy, which may negatively impact quality of life and increase the risk of non-malignant mortality. This study evaluated whether volumetric modulated arc radiotherapy (VMAT) offers improved target volume coverage and better protection of organs at risk (OARs) compared to three-dimensional conformal radiotherapy (3D-CRT) in patients with early glottic cancer. Methods: Computed tomography (CT) images from 13 patients with early glottic cancer were analyzed to compare the dosimetric plans of 3D-CRT and VMAT. Dose-volume histogram (DVH) parameters were assessed across 26 treatment plans, including the homogeneity index (HI) and conformity index (CI) for the planning target volume (PTV). Specific dose-volume metrics for OARs, such as the carotid arteries, thyroid gland, and spinal cord, were also compared between the two modalities. Results: VMAT plans demonstrated significantly higher PTV mean dose, PTV maximum dose, and volume receiving 95% of the prescribed dose compared to 3D-CRT plans (p = 0.047, 0.045, and <0.001, respectively). VMAT also showed superior homogeneity and conformity indices for the PTV (p = 0.003 and 0.001, respectively). Additionally, the mean doses to the right and left carotid arteries and the thyroid gland were significantly lower with VMAT (p = 0.009, 0.03, and <0.001, respectively). Conclusion: VMAT provides superior dose-volume parameters for target coverage, homogeneity, and sparing of OARs compared to 3D-CRT in the treatment of early glottic cancer. These advantages suggest that VMAT may be particularly beneficial for patients at increased risk of cerebrovascular complications.