Background/Context: In a recent review of culturally relevant instruction and reading comprehension, Fairbanks, Cooper, Masterson, and Webb (2009) highlighted the paucity of research available to support the widespread claim in the literacy field that "students' social and cultural practices are deeply intertwined with literacy learning" (p. 600). They noted that few studies have examined comprehension as an outcome variable and that most studies have been qualitative and focused upon participation structures and interactional patterns. The research reported here addresses these deficiencies in the knowledge base. In two related studies, it quantitatively investigated the achievement gains of African American children enrolled in a 10-week after-school reading program given three text conditions--exclusive use of culturally relevant texts, exclusive use of non-culturally relevant texts, and intermittent use of culturally relevant texts. Purpose: The purpose was to examine the influence of culturally relevant instructional texts on African American students' reading gains. The first of the two studies investigated whether children who read culturally relevant texts exclusively for instruction would show a different pattern of reading gain than those who read texts that were not culturally relevant. The second investigated whether those who read culturally relevant texts exclusively would show a different pattern of gain than those who read them intermittently. Research Design: The first study employed a quasi-experimental, control group design to evaluate reading progress given two conditions, exclusive use of culturally relevant instructional texts and exclusive use of texts that were not culturally relevant, while the second drew upon archival data and used a matched pair design to compare the reading gain of children in the first study's exclusively culturally relevant condition to that of children who attended the program in semesters not associated with the first study and who read culturally relevant instructional texts only intermittently in the program. Findings: Across the studies, the analyses revealed that (1) the comprehension growth of children who read culturally relevant texts exclusively significantly outpaced that of peers who did not read them as well as those who read them intermittently, (2) the contextual word recognition growth of children who read culturally relevant texts exclusively significantly outpaced that of peers who did not read them and nearly significantly outpaced that of peers who read them intermittently, and (3) children's word recognition in isolation growth did not differ significantly. Conclusions: The findings provide empirical support for perspectives that view students' socio-cultural subjectivities as integral to learning. They demonstrate that instruction grounded in culturally relevant texts can produce superior achievement gains for African American children. The amount of instruction associated with the children who made superior gains in this research would be fairly easy to accommodate within schools. The results of this research indicate that it may be worth the effort.