We systematically reviewed and compared the clinical outcomes of thoracoscopic sympathectomy (TS) at different denervation levels for palmar hyperhidrosis. We searched PubMed, Ovid MEDLINE, EMBASE, Web of Science, ScienceDirect, the Cochrane Library, Scopus and Google Scholar for relevant studies published during 1990-2016. Symptom resolution, patient satisfaction, compensatory sweating (CS), recurrence, dry hands and gustatory sweating were assessed. We selected 13 studies from 2228 for the final analysis. A comparison of T2 vs. T3 TS revealed that T3 TS reduced the risk of CS (95% confidence interval [CI]: 1.36-3.19, p = 0.0007) and moderate-to-severe CS (95% CI: 2.14-7.87, p < 0.0001). No significant differences were found in patient satisfaction, symptom resolution, and incidence of dry hands and gustatory sweating. A comparison of T3 vs. T4 TS revealed that T4 TS reduced the risk of CS (95% CI: 2.87-9.53, p < 0.00001), moderate-to-severe CS (95% CI: 2.54-5.83, p < 0.00001), dry hands (95% CI: 4.07-18.13, p < 0.00001) and gustatory sweating (95% CI: 1.53-7.32, p < 0.003), and improved patient satisfaction. No significant differences were found in symptom resolution and recurrence. T4 TS appears to be more useful than T3 or T2 TS for PH.