[Background] The effect of tonsillectomy on immune function has been clinically controversial and also a major concern for parents of affected children. This study sought to understand the true impact of tonsillectomy on the immune system. [Methods] The literature analyzing the effects of tonsillectomy on the immune system was retrieved from MEDLINE, EMBASE, and COCHRANE databases. Time was searched up to December 2014 using keywords and medical subject terms. The abstracts of all detected literature were browsed to determine if the literature met the inclusion criteria. The cited literature was cross-checked manually. We examined the results and conclusions of each study and categorized them as either for or against the hypothesis that tonsillectomy had an adverse effect on the immune system. [Results] This study analyzed 35 studies, published from 1971-2014, including a total of 1997 patients. Only four studies (11.4%), with a total of 406 patients (20.3%), found a negative effect of tonsillectomy on the immune system. We performed separate Meta-analyses of various humoral and cellular immune indicators (e.g., total and specific plasma 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 immune 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 meaningful negative effects on the immune system. Future studies should use uniform laboratory tests, including humoral and cellular immunity, to compare and analyze changes in immune function in children before and after surgery in the short and long term. The results of this Meta-analysis should allay the concerns of surgeons and parents of children about the possible adverse clinical consequences of tonsillectomy. If future studies in this area are to be conducted, a uniform standard protocol should be used to avoid heterogeneity in the literature.