The study examined individual factors and social factors that influence adolescent students' achievement in mathematics. The predictive model suggested direct positive effects of student intelligence, self-rated openness and parental education on achievement in mathematics, whereas direct effects of extraversion on measures of achievement were negative. Indirect positive effects of intelligence, self-rated conscientiousness, student-perceived mathematics teacher's press for understanding and mastery goal, and a negative effect of student-rated parental academic pressure on course achievement were mediated through the students' self-efficacy in mathematics. The findings highlight the important role that individual differences in ability and personality, as well as student perceptions of parent and teacher academically related variables, play in the students' performance in mathematics. (Contains 2 tables and 1 figure.)