While research on second language teacher cognition (SLTC) has significantly developed over the past three decades, this line of inquiry has not paid adequate attention to material development/evaluation as compared to the key role that materials play in teachers' daily practice. In response to this gap, in this study we adopted the theoretical stance of teacher maxims as part of SLTC, and explored eight Iranian English language teachers' maxims in relation to material evaluation. Data were collected from a researcher-adapted questionnaire and semi-structured interviews, and analyzed based on content analysis. Data analyses revealed that the teachers evaluated their implemented material in light of both positive and negative aspects, with the positive sides being more pedagogical and the negative dimensions being more institutional and sociocultural. Additionally, the teachers' maxims indicated that materials should not only serve pedagogical issues, but they should also embrace emotions and sociocultural particularities so that educational stakeholders, especially students, develop socio-educational capitals. Based on the findings, we provide implications for teacher educators to run professional development courses that embrace personal, interpersonal, and sociocultural particularities in the courses to enhance teachers' awareness of the role materials play in their SLTC growth.