Background. It is very normal for kids to get tonsillitis. Tonsillectomy is the most common surgery done on kids who get tonsils over and over again. When a child is three to ten years old, their tonsils are at their most immune-boosting. Because of this, the tonsils stand out more during this time and eventually show age-dependent involution. Aims of the study. Evaluating the role of vitamin D, interleukin 6, and thyroid-stimulating hormone in tonsilitis and the relationship of these biomarkers in controlling the severity of the disease in children. Methodology. A case- control study was conducted including 30 children with chronic pharyngitis with an average age of 14.19 years, as well as a control group of 25 healthy children. The study took place at the Al-Kadhimiya Teaching Hospital from 10/2/2022 to 10/8/2023, after approval by the Research Committee of the College of Medicine at Al-Nahrain University and obtaining verbal consent from the parents. Blood samples were collected and the necessary analyzes were performed. CRP, ASO, and interleukin-6 levels were measured using an ELISA. The total number of white blood cells was calculated using a Sysmex CBC device, and the ESR was measured with a Fast ESR device. TSH and vitamin D levels were analyzed using a Cobas E411 device. Result. The levels of several biochemical and immune markers were very different between the patient group and the control group (P< 0.001). In the patient group, levels of ASOT, CRP, ESR, WBC, TSH, and IL-6 all went up, while levels of vitamin D went down. The results also showed that TSH and IL-6 levels were different in men and women with chronic tonsillitis. However, there were no statistically significant changes in the other indicators (P> 0.05). Conclusions. The results indicate that there are significant differences in biochemical and immunological indicators between children with chronic tonsillitis and healthy children. This can be explained by the increased inflammatory response in patients, which raises ASOT, CRP, ESR, and IL-6 levels and lowers vitamin D levels.