Objective: During the postoperative period, most patients with otosclerosis report vertigo and/or nausea caused by interventions within the inner ear. The aim of this study was to evaluate both early and late vertigo associated with hearing improvement after stapes surgery for otosclerosis. Methods: The analysis included 170 patients admitted to the hospital undergoing their first surgery for otosclerosis. Audiological diagnostics, surgical techniques, and symptoms reported by the patients were all analyzed. Results: A statistical correlation and an unfavorable influence of late, undesired symptoms, such as vertigo, nausea/vomiting, and nystagmus, on final hearing improvement after surgical treatment of otosclerosis were found. Prostheses that were too long or placed too deep within the inner ear space were the most frequent cause of both vertigo and lack of hearing improvement observed after stapedotomy. Conclusions: A significant negative influence on bone conduction thresholds, particularly at 2000 Hz, was associated with vestibular symptoms persisting for 7 days after the surgery. Symptoms of impaired bony labyrinth function after stapedotomy, persisting for more than 1 year, were associated with insufficient reduction of the air–bone gap and worse improvement in bone conduction thresholds at 1000 and 2000 Hz. The cause of both problems was related to a prosthesis that was too long or placed too deep in the inner ear during stapedotomy.