Background: The phenotypic presentation of overt hypothyroidism during adolescence is less well characterized. The aim of the study was to study the phenotypic presentation of patients with overt hypothyroidism presenting during adolescence (age 9–18 years). Methods: Records of adolescent patients with overt hypothyroidism (thyroid stimulating hormone [TSH]>10 mIU/L) were retrospectively analyzed for presenting complaints, height and pubertal status. Results: A total of 67 patients (40 females and 37 males, average age 13.2+2.3 years) with a mean TSH of 241.3±336.6 mIU/L were included. The commonest presentation was short stature in 46.2% of patients followed by neck swelling (16.4%) and weight gain (11.9%). The mean height standard deviation score (SDS) was −2.5+2.11, 43% of patients had less than 3 SDS. The height age and bone age were around 3 years less than the chronological age. The bone age significantly correlated with the height age but not with TSH levels. Three patients referred from neurology with primary complaints of headache had pituitary hyperplasia and one presented with hypokalemic periodic paralysis. Seven had delayed puberty and one patient had early periods due to huge ovarian cysts. Conclusions: In the present study, severe short stature and uncommon phenotypic presentations were a consequence of long-standing severe untreated hypothyroidism.