Background Glottal insufficiency results in glottal gap between the two vocal folds, which in turn might cause dysphonia, dysphagia, and breathing problems. Vocal fold injection is considered a safe, reliable, and highly effective method of treatment. The purpose of the present study was to assess voice outcomes and complication rates in patients with glottal insufficiency undergoing injection laryngoplasty (IL) under local versus general anesthesia before, 1 week then 1 month after IL. Results Examined patients were 13 males and 12 females, suffering from dysphonia due to glottal insufficiency with mean age 43.68 ± SD 14.55. Unilateral vocal fold paralysis (UVFP) was diagnosed in seventeen cases, vocal fold scarring in six cases, presbylarynx in one case, and sulcus vocalis in one case. IL was performed in 18 cases under local anesthesia, and 7 under general anesthesia. Hyaluronic acid was injection material in 23 cases and calcium hydroxylapatite in two cases. IL by either local or general anesthesia has improved the patients’ auditory perceptual analysis of voice quality as assessed by “GRBAS” scale and Voice Handicap Index (VHI). There were four (16% of all injections) minor and self-limited complications (12% under local and 4% under general anesthesia). Conclusion Injection laryngoplasty performed under local and general anesthesia offers similar voice outcomes, but with slightly higher self-limited complications in IL under local anesthesia.