Background/Context: Teachers affect student performance through their interaction with students in the context of the classrooms and schools where teaching and learning take place. Although it is widely assumed that supportive working conditions improve the quality of instruction and teachers' willingness to remain in a school, little is known about whether or how the organizational structure of charter schools influences teacher working conditions. Purpose/Research Question: This article compares teacher working conditions in charter and traditional public schools and among various types of charter schools. In doing so, it seeks to understand whether the different working conditions are influenced by the intrinsic institutional features of charter schools such as autonomy and competition, or by the extraneous factors such as measurable school and teacher characteristics. Research Design: This study utilized data from the 2003-2004 Schools and Staffing Survey (SASS), the nation's most extensive survey of K-12 schools and teachers, both for charter schools and traditional public schools (TPSs). This article is a quantitative analysis that involves three main steps. First, based on the responses to the SASS teacher questionnaire, confirmatory factor analysis was performed to generate multiple factors corresponding to key dimensions of teacher working conditions. Second, propensity score matching was used to pair charter schools with TPSs that are similar in terms of school location, educational level, school type, and student demographics. This matching process mitigates the confounding effects of these extraneous factors on teachers' perceptions of working conditions. Finally, a series of weighted Hierarchical Linear Models were utilized to compare teachers' perceptions of working conditions between charter and traditional public schools, controlling for teacher and school characteristics. Conclusions/Recommendations: The results show that charter and traditional public school teachers perceive their working conditions to be similar in many regards, including principal leadership, sense of community and collegiality, classroom autonomy, opportunities for professional development, and adequacy of instructional supplies. However, charter school teachers perceive that they have significantly more influence over school policies, but a heavier workload than traditional school teachers. Among charter schools, district-granted charter schools show consistently more supportive working environments than charters granted by other organizations. This implies that state policy can have some indirect influence over charter school working conditions by providing substantial administrative support and oversight to charter schools authorized by independent organizations other than the established structure of school districts.