The purpose of this study was to exam me the effects of science self efficacy,rnscience achievement motivation, attitudes toward science andrngender on science performance of high school students, and to show therndifference between males and females among the variables. A total of 202rngrade 10 students (108 males and 94 females) were involved in the studyrnfrom Debre Brehan General Secondary School. A t-test and multiplernregression analysis were employed to analyze the data. The resultrnindicated statistically significant gender difference in science self-efficacyrn(chemistry, physics and biology) and science performance (chemistry,rnphysics and biology). There were also significant gender difference inrnstudents' attitudes toward chemistry and physics. However, there were nornsignificant gender difference in students' attitude towards biology and inrnscience achievement motivation (chemistry, physics and biology). Multiplernregression analysis also showed that science self-efficacy, SCIencernachievement motivation, attitude towards science and gender significantlyrncontributed to the variation in science performance. Because of thernsignificance difference observed between male and female students, andrnsignificant contribution of independent variables on science performance,rnrecommendations are forwarded for the concerned bodies.