This study was based on a survey of secondary school students’ mathematics achievement. Students of both the gender constitute the population of this study. Sample of the study was 925 students i.e. 453 government school students (223 males and 230 females) and 472 private school students (241 males and 231 females) of 9^th grade selected randomly from 10 private and 10 government schools located in Chandigarh. Mathematics achievement test prepared and standardized by the investigator to examine the mathematics achievement of male and female students at secondary school level was used. Descriptive statistics and t-test with P < 0.05 level of significance were used for data analysis. Significant differences were found between government and private school adolescents with regard to achievement in mathematics. Government school male and female adolescents differ significantly, however Private school male and female students do not differ with regard to achievement in mathematics.