The gender gap in achievement is one of the main challenges that face the educational system in Jordan. Since 1989, educational reform plans have attempted to reduce gender gap in achievement. However, the gender gap in science achievement according to PISA 2015 was higher than that of other participating countries. This study aimed to show the trends, and determine the factors associated with the gender gap in science achievement. The data were obtained from 7267 students, who participated in PISA 2015. Descriptive statistics and multiple regression methods were used, for which the results showed that the gap became wider with the same direction since 2006. In addition to that, the study findings suggested that environmental awareness, and sense of belonging to school are the most important factors associated with gender gap among other personal factors.