Background: This study aimed to evaluate the impact of iron replacement therapy on thyroid function in children with iron deficiency anemia (IDA). It assessed hematological parameters and thyroid function before and after iron supplementation to determine the correlation between iron status and thyroid hormone metabolism. Material and Methods: A total of 120 children aged 2-12 years diagnosed with IDA were included in the study. Baseline assessments included complete blood count (CBC), serum iron, ferritin, total iron-binding capacity (TIBC), and thyroid function tests (TSH, FT3, FT4). All participants received oral ferrous sulfate (3 mg/kg/day) for three months. Compliance was monitored through regular follow-ups. Post-treatment blood samples were analyzed for changes in hematological and thyroid function parameters. Statistical analysis was performed using appropriate methods, with a p-value of <0.05 considered significant. Results: Significant improvements in hematological and thyroid function parameters were observed after iron therapy. Hemoglobin levels increased from 8.50 ± 1.20 g/dL to 11.40 ± 1.30 g/dL (p=0.001), serum iron improved from 35.60 ± 5.40 µg/dL to 85.30 ± 7.10 µg/dL (p=0.002), and ferritin levels rose from 9.80 ± 2.30 ng/mL to 45.20 ± 4.80 ng/mL (p=0.001). TSH levels decreased significantly from 4.20 ± 0.90 µIU/mL to 2.80 ± 0.75 µIU/mL (p=0.010), while FT3 and FT4 levels increased by 52.38% and 35.29%, respectively. The proportion of children with normal thyroid function increased from 65.00% to 85.00%, while cases of subclinical hypothyroidism and overt hypothyroidism decreased significantly post-therapy. Correlation analysis showed that improved iron status was associated with lower TSH and higher FT3 and FT4 levels. Conclusion: Iron replacement therapy significantly improves both hematological and thyroid function parameters in children with IDA. The reduction in TSH levels and the increase in FT3 and FT4 post-therapy suggest a strong link between iron status and thyroid hormone metabolism. These findings highlight the importance of early iron supplementation and routine thyroid screening in children with IDA to prevent thyroid dysfunction and optimize overall health.