Objective: To evaluate and compare the normative and subjective need for orthodontic treatment within different age groups in Turkey. Methods: One thousand and sixteen patients from seven different demographic regions of Turkey (Marmara, Black Sea, East Anatolia, Southeastern Anatolia, Mediterranean, Aegean, and Central Anatolia Region) (mean age +/- SD: 12.80 +/- 3.57 years) were randomly selected and divided into six age groups (7-8,9-10,11-12,13-14,15-16, and 17-18 year-olds) and categorized according to the dental health component (DHC) of the index for orthodontic treatment need (IOTN). Additionally, the patients were asked to indicate the photograph that was most similar to their own dentition from the 10-point scale of the aesthetic component of IOTN. Results: The DHC of IOTN was not significantly different between the six age groups (P > 0.05). However, no/slight need (aesthetic component 1-4) for orthodontic treatment according to AC of IOTN was significantly higher in 13-14,15-16, and 17-18 age groups than 7-8, 9-10, and 11-12 age groups (P < 0.05). No sex differences were found in both DHC and aesthetic component of IOTN between age groups (P > 0.05). Conclusion: The normative need distribution was homogeneous within all the age groups according to DHC. However, the subjective need for orthodontic treatment was higher in the younger age groups.