This study focuses on illuminating Kenya's urban high school teachers' perceptions of students' diversity and how these differences influence their curriculum implementation, pedagogy, and students' classroom interactions in the learning process. Located within theoretical frameworks of intersectionality and critical pedagogy, the study shows how multiple layered identities and differences identified by teachers interplay and intersect to influence their performance and students' academic success. The theoretical debate over critical pedagogy in diverse contexts shows how Kenya's high school teachers effectively develop classroom environments that address differences and acknowledge arrays of factors that create inequalities. Findings also show that teachers' work continue to be informed by government and institutional policies that favor uniformity and conformity creating contradictions and dilemmas for them. The study applies a mixed qualitative methodology based on interpretive and descriptive phenomenology to inform the study. Participants were selected based on purposive sampling from urban high schools in western Kenya. Data for the study were generated through baseline questionnaires, field interviews, classroom observations, and analysis of archival documents. Findings highlighted arrays of factors identified by participants as contributing to students differences in their specific context. Differences identified by teachers that were common across institutions were academic abilities, entry behavior, primary education backgrounds, proficiency in English language, socio-economic status, and students' motivational status. Some of the factors perceived to influence teaching and learning differed across disciplines, gender of the participants, and the nature of the schools. It was concluded that the impact of these differences on teaching and learning needs to be addressed if high school access, quality, and subsequent academic performance is to be realized for.