Within low-income communities in low- and high-resource countries, there is a profound need for more effective schools that are better able to foster child and youth development and support student learning. This paper presents a theoretical framework for understanding the role of teacher ecology in influencing teacher effectiveness and, through this, classroom learning. "Teacher ecology" refers to teachers' own characteristics and well-being as they pertain to, and are influenced by, their proximal environments. This paper focuses on three aspects of teacher ecology: (1) teachers' skills, abilities, and knowledge; (2) teachers' own poverty, stress, and health; and (3) structural (e.g. school/government policies around payment) and cultural (e.g. social norms around teaching) supports for/barriers to teaching. The model presented in this paper focuses on teaching within resource deprived settings and much of the literature reviewed in this paper is drawn from low- and middle-income countries such as Kenya, Nigeria, Benin, India, Peru, Malawi, and China. This said, the theoretical model is a broad-gauged and is simultaneously informed by and has implications for research and practice in low- and middle-income countries and low-income communities within higher-income countries. As such, literature is also drawn from high poverty areas in wealthy countries like the United States. This paper argues that attempts to improve school quality and increase student learning in resource deprived areas have been hindered by a lack of attention to teachers' lives, the barriers they face, and the supports they need--inside and outside of school. The model presented is adapted from Tseng and Seidman's (2007) systems framework for understanding youth social settings. ness / Applicability of Method: The framework presented in this paper suggests a number of next steps for researchers seeking to better support teacher effectiveness. First, there is a need for more descriptive research on the individual, school and societal influences on teachers' attendance, mobility, and classroom performance in varying low-income communities. Some of the aspects identified in this paper are likely to have no bearing in specific communities and others may be hugely influential but overlooked in current education policies. Second, the field would benefit from a better understanding of how, for whom, and under what conditions different educational initiatives work (or don't work). Third, this contextual work should be incorporated into process evaluations in advance of selecting an intervention for implementation; and the implementation plan itself should leave space for altering the intervention post baseline descriptive findings. To illustrate, using monitoring to try to increase teacher attendance in a community where teachers are missing school due to district policies is unlikely to yield the desired results. Fourth, impact evaluations should seek to increase the breadth of baseline community measures collected pre-intervention. Such measures can inform why an intervention may not be working as well as for whom and under what conditions it is working. Finally, quantitative researchers should, where possible, include open-ended measures in their studies to better understand teachers' experiences as well as the supports and barriers they encounter. One figure is appended.