Puberty and its consequence changes are one of the most important events of each person's life. Knowledge about puberty health lead to successful passage of this period. This study was aimed to determine factors predicting the knowledge of girl students about puberty health in Tabriz high schools. This study was a cross-sectional study conducted on 364 students in seventh and eighth grades in 2015. The participants were selected using random cluster sampling. Their knowledge and socio-demographic characteristics about puberty health were collected using selfcompleted questionnaires which is standardized questionnaire for Iran society. General Linear Model was used for determining the socio-demographic predictors of knowledge about puberty health. The mean score of students' knowledge was 8.26±2.21 (in the range of 0-15 scores). Fathers' education (P=0.023) and previous obtained information (P=0.001) were knowledge predictors. Regarding the mean score of students' knowledge and their direct relationship some factors such as father's education, it is suggested to increase the knowledge of parents especially mothers about puberty health by health providers at schools and the related organization using in present learning pamphlets, sessions and classes.