The purpose of this study is to better understand how math teachers' effectiveness as measured by value-added scores and student satisfaction with teaching is influenced by school's working conditions. The data for the study were derived from 2009 to 2010 Teacher Working Condition Survey and Student Perception Survey in Measures of Effective Teaching Project. Using the structural equation modeling and other related methods, several models of teacher effectiveness were estimated. The findings indicate that among the examined working condition factors, support for instruction and for student conduct management have significant effects on teachers' value-added scores in mathematics. Moreover, the student satisfaction with teaching seems to have a mediating effect on value-added scores. The findings of the study significantly contribute to a better understanding of the effects of working environment on math teachers' effectiveness and how improvement in working conditions can enhance math teachers' performance.