Objective: To evaluate the treatment outcomes and associated factors in myasthenia gravis patients after thymectomy. Subjects and Methods: The study included 66 myasthenia gravis patients who underwent thymectomy at the Neurology Center and Thoracic Surgery Department of Bach Mai Hospital from October 2019 to January 2023. Results: The rate of improvement after thymectomy was 77.3%. The long-term stable rate was 33.3%; pharmacologically stable rate was 18.4%; minimal manifestation rate was 25.8%; 10.6% of patients showed no improvement, 7.6% had worsening conditions, and 4.6% of patients died. The average time to improvement was 20.25 months, with a median of 18 months. The likelihood of improvement in patients who underwent surgery within one year of symptom onset was 5.04 times higher than those who had surgery after one year, with p<0.05. Patients without bulbar or respiratory symptoms had a higher likelihood of improvement compared to those with symptoms. Specifically, patients without dysphagia had a significant improvement (p<0.05, OR=9.80, 95%CI: 1.20–80.35), and patients without dyspnea had an OR=5.00 (95%CI: 1.31–19.07), both showing statistically significant relationships with p<0.05. Patients in clinical stages I and IIA (mild stage) had a higher likelihood of improvement compared to those in stage III (p<0.05, OR=14.67, 95%CI: 1.16–185.23; OR=12.67, 95%CI: 1.56–102.30). Patients in the mild clinical stage had a significantly higher likelihood of improvement compared to those in moderate and severe stages (p<0.05, OR=164.50, 95%CI: 152.3–708.50). Conclusion: The majority of patients showed improvement after surgery, with an average improvement time of 20.22 months. Factors associated with improvement after thymectomy included: surgery performed within one year of symptom onset, absence of bulbar and respiratory symptoms, and mild clinical stages (I, IIA).