The developmental growth of any society depends greatly on the progression and innovations made by students' in science, technology, engineering and mathematics. The current study determines the moderating effect of gender on the relationship between senior school physics students' STEM self-efficacies and science identity. The study was a co-relational study that employed the use of adopted questionnaires as found in the previous literatures to elicit information on students' STEM self-efficacies like science self-efficacy, engineering/technology self-efficacy, mathematics self-efficacy and students' science identity. The study adopted the usage of structural equation model and collected data were analyzed by SmartPLS software. The findings of the study revealed that physics students' science self-efficacy ([beta]=0.174, p<0.05), mathematics self-efficacy ([beta]= -0.296, p<0.05) and engineering/technology self-efficacy ([beta]= -0.600, p<0.05), and, has negative, positive, weak, substantial and significant relationship with physics students' science identity. The study further revealed that gender as a moderator variable significantly moderated the indirect relationship between physics students' science, technology, engineering and mathematics self-efficacies and their science identity. The study recommended that the physics students should be encouraged to see themselves as science person as this would influence their interest and decision to pursue a future career in science, technology, engineering and mathematics fields.