Abstract-The identification of the onset of pubertal growth phase in growing patients is very important for orthodontists to determine orthodontic treatment planning and timing. The timing of growth phase can be assessed using chronological age, skeletal age, physiological age, dental age and biomarkers. ALP is one of the biomarkers that can be easily obtained from saliva. The increase of ALP levels in growing subjects is one of the indications of bone mineralization. The objective of this study was to assess the level of ALP in growing subjects in relation to the pubertal growth phase and age. This research was an observational analytic research with cross sectional design. Samples in this study consisted of 57 healthy growing female subjects (age ranging from 8 to 15 years). Growth phase was assessed through the cervical vertebral maturation (CVM) method described by Hassel and Farman. The subjects were divided into three groups according to their growth phases, which were prepubertal (CVM 1 and CVM 2), pubertal (CVM 3 and CVM 4), and post pubertal (CVM 5 and CVM 6). Unstimulated whole saliva collected from each subject and the level of ALP were measured using spectrophotometer. Results showed that peak levels of ALP were observed in pubertal growth phase: 233.39 ± 106.29 (IU/L), followed by prepubertal growth phase: 192.87 ± 69.02 (IU/L), and post pubertal growth phase: 79.20 ± 31.41(IU/L). The highest ALP levels were found at 10-11 years, and at 8-9 years, 12-13 years, and 14-15 years respectively. As conclusion, the level of ALP in saliva can be used as biomarker for the pubertal growth phase identification to determine orthodontic treatment planning and timing.