Objective: To establish the local data on the growth of ear in Hong Kong children and provide a reference for the timing of reconstruction in unilateral microtia. Methods: We reviewed case notes of paediatric patients up to 18 years of age who had attended our Ear, Nose and Throat Out-patient Clinic from March to November 2017. We recorded the pinna length of these patients and that of their parents, compared the patients’ ear length against that of their parents, and investigated any discrepancy of pinna. Results: We recruited 226 local individuals (139 males and 87 females). The patients were divided into different age groups. The means of ear length of patients were compared with the mean length of pinna of their parents. Data of boys and girls are analyzed separately. Boys at 7-8 years old achieved 87.33% and 93.54% of their fathers’ and mothers’ ear length respectively. Girls at 7-8 years old achieved 83.00% and 90.80% of their fathers’ and mothers’ ear length respectively. Moreover, the average ratio of the length of left and right ear ratio is 97.3% in all groups of children. Conclusions In Hong Kong children, at the age of 7-8 the ear approaches the size of normal adult ear and is the feasible age with less asymmetry after reconstruction of the microtia.