Purpose: The aim of this study was to compare theory of Mind, IQ and attention of normal and hypothyroidism students. Materials & Methods: The research method was causal – comparative. The statistical society of it includes students studying in first-grade section of Saveh city that among them, 346 people were selected using random cluster sampling. In the first stage, 30 students were diagnosed with hypothyroidism by clinical examination and measurement of urinary iodine and 30 people were selected as healthful group (witness). In the second stage, the revised Wechsler Intelligence Scale for Children and the color-word Stroop test was performed to measure IQ, theory of mind and attention in both hypothyroidism and normal groups. Multivariate variance analysis, the mean and standard deviation were used to test the hypothesis. Findings: The results showed that there was a significant difference between theory of mind, the amount of IQ and attention of normal students with hypothyroidism students. The mean verbal and nonverbal and overall IQ of healthy group compared to hypothyroidism group was respectively 21.5 and 25 and 25.5 more .also, the theory of mind and attention in hypothyroidism group was reduced compared to normal group. Theory of mind, attention and IQ of hypothyroidism students was lower than normal students. Conclusion: in addition to intelligence, theory of mind and attention of hypothyroidism students was different from normal students.