The main purpose of this study was to investigate the effects of gender difference, attitude towards mathematics, parents' education level, and parents' locality in relation with their mathematics achievement of high school students. To this end, an extensive review of the available literature was made. The review was focused on four factors (i.e. gender, students' attitude towards mathematics, parents' educational level, and parents' locality) and mathematics achievement. Based on review of related literature, basic research questions were constructed and framed. Three selected general secondary schools of Awi zone were used as a source of data for this study. The study used mathematics achievement test and questionnaire as instruments of data collection. The questionnaire and mathematics achievement test were administered 240 students (120 males and 120 females) of grades nine and ten that were chosen based on simple random sampling techniques. The responses of the students and the results of documentary detailed examination have been analyzed and interpreted. Major statistical techniques, such as ttest product moment correlation coefficient, and multiple regressions were applied for data analyses. Results of the analyses indicated that mathematics achievement was related to gender, mother's education level mathematics attitudefather's education level and parents' locality with statistical significance. All of these five variables together explain about 47.3 percent of mathematics achievement, with gender 36%, with mathematics attitude 4.3%, with mother's education level 5.7%, withfather's education level 1.2%, and with parents' localityO.l% among grade nine students. Further, mathematics achievement was related to gender, mathematics attitude, mother's education level, father'S education level, and parents' locality with statistical significance. All of these five variables together explain about 44.8 percent of mathematics achievement, with gender 35.6%, with mathematics attitude 8.7%, with parents' Locality 0.4% and with mother's education level 0.1% among grade ten students