Background: Controversy exists concerning whether tenotomy or tenodesis is the optimal surgical treatment option for proximal biceps tendon lesions. Purpose: To evaluate the clinical outcomes after arthroscopic tenodesis and tenotomy in the treatment of long head of the biceps tendon (LHBT) lesions. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was performed by searching PubMed, the Cochrane Library, Web of Science, and Embase to identify randomized controlled trials (RCTs) and cohort studies that compared the clinical efficacy of tenotomy with that of tenodesis for LHBT lesions. A standardized data extraction form was predesigned to obtain bibliographic information of the study as well as patient, intervention, comparison, and outcome data. A random-effects model was used to pool quantitative data from the primary outcomes. Results: A total of 21 eligible studies were separated into 3 methodological groups: (1) 4 RCTs with level 1 evidence, (2) 3 RCTs and 4 prospective cohort studies with level 2 evidence, and (3) 10 retrospective cohort studies with level 3 to 4 evidence. Analysis of the 3 groups demonstrated a significantly higher risk of the Popeye sign after tenotomy versus tenodesis (group 1: risk ratio [RR], 3.29 [95% CI, 1.92-5.49]; group 2: RR, 2.35 [95% CI, 1.43-3.85]; and group 3: RR, 2.57 [95% CI, 1.33-4.98]). Arm cramping pain remained significantly higher after tenotomy only in the retrospective cohort group (RR, 2.17 [95% CI, 1.20-3.95]). The Constant score for tenotomy was significantly worse than that for tenodesis in the prospective cohort group (standardized mean difference [SMD], -0.47 [95% CI, -0.73 to -0.21]), as were the forearm supination strength index (SMD, -0.75 [95% CI, -1.28 to -0.21]) and the Simple Shoulder Test (SST) score (SMD, -0.60 [95% CI, -0.94 to -0.27]). Conclusion: The results demonstrated that compared with tenodesis, tenotomy had a higher risk of a Popeye deformity in all 3 study groups; worse functional outcomes in terms of the Constant score, forearm supination strength index, and SST score according to prospective cohort studies; and a higher incidence of arm cramping pain according to retrospective cohort studies.