This study aims to reveal the effects of teacher competency, learning motivation, and home environment on students' learning achievement. This study was associative research employing quantitative data. The research population was all senior high school students of class XI social group in 45 public and private high schools in Yogyakarta City. The student sample of 122 students was established by using the proportional random sampling area technique. The data were collected by using a questionnaire for teachers' competency, learning motivation, home environment, and documentation for learning achievement variable. The testing of the instrument validity was done through expert judgment and factor analysis, while the reliability testing used Alfa CronbachThe result of this study shows that: (1) teachers' competency shows significant effects on students' learning achievement with the effective contribution (R) of 6.1%; (2) learning motivation shows significant effects on students' learning achievement with the effective contribution (R2) of 36.8%; (3) home environment shows significant effects on students' learning achievement with the effective contribution (R2) of 4.1%; (4) teachers' competency, learning motivation and home environment together show positive and significant effects on students' learning achievement with the effective contribution (R) of 41.4%. This means that the independent variables teachers' competency, learning motivation, and home environment effects on students' learning achievement partially and together.