Background <p>Early glottic carcinoma primarily affects the vocal folds and most commonly presents with the symptom of dysphonia, which is an effect of the tumor interfering with normal vocal fold vibration. Radiotherapy for early glottic carcinoma is highly effective in controlling the tumor while preserving the larynx and voice. The aim of this study was to evaluate changes over time in voice outcomes among patients with early stage glottic cancers treated with definitive radiotherapy using stroboscopy as well as voice acoustic analysis.</p> Methods <p>The assessment was applied on 24 patients with T1 and T2 glottic carcinoma. It was conducted pre-radiotherapy, 3 months and 6 months post-radiotherapy as follow-ups. The assessment included laryngoscopic, videostroboscopic examination, and voice acoustic analysis.</p> Results <p>Marked improvement was found in videostroboscopic parameters, with parameters highly significant differences across the three phases for nearly all stroboscopic parameters, <i>p</i>-values (&lt;0.001), with a significant difference noted specifically for the periodicity of mucosal waves in the right vocal fold <i>p</i>-value (0.005). Significant improvement was detected in voice acoustic analysis parameters, including the increase in harmonic to noise ratio and maximum phonation time, and reduction in jitter and shimmer by 6 months (<i>p</i> &lt; 0.001).</p> Conclusions <p>The overall outcomes of the current study pointed to improved glottic manifestations based on videostroboscopy parameters and voice acoustic analysis parameters by 6 months post-radiotherapy.</p>