[Background] The effect of tonsillectomy on immune function has been a clinical controversy and a major concern for parents of affected children. The present study was an attempt to understand the real impact of tonsillectomy on the immune system. [Methods] Literature analyzing the effect of tonsillectomy on the immune system was retrieved from MEDLINE, EMBASE and COCHRANE databases. The time period up to December 2014 was searched using keywords and medical subject terms. Abstracts of all retrieved literature were browsed to determine whether the literature met the inclusion criteria. Manual cross-checking of cited literature was performed. The results and conclusions of each study were examined and categorized as supporting or opposing the hypothesis that “tonsillectomy adversely affects the immune system”. [Results] Thirty-five studies, published between 1971 and 2014, were analyzed in this study, including a total of 1,997 patients. Only four studies (11.4%) with a total of 406 patients (20.3%) found that tonsillectomy had a negative effect on the immune system. We performed separate Meta-analyses of various humoral and cellular immune indices (e.g., plasma total and specific Ig, SecIgA, cellular immune parameters, and antigen-specific Ig) in the studies. The results showed additional evidence suggesting that tonsillectomy has no adverse clinical or immunologic effects on the immune system. Limitations of the study include heterogeneity in diagnostic tools, timing of testing, indications for tonsillectomy, and patient age. [Conclusion] There is sufficient evidence to conclude that tonsillectomy does not cause clinically significant negative effects on the immune system. Future studies should use uniform laboratory tests, including humoral and cellular immunity, to compare and analyze short- and long-term changes in immune function in children before and after surgery. The results of this Meta-analysis should allay the concerns of surgeons and parents about the potential for adverse clinical consequences of tonsillectomy.