For more than a decade, government primary-school teachers in many parts of India have been using mathematics textbooks based on National Curriculum Framework 2005 (NCF 2005). While curriculum and textbook development is often debated, teachers’ use of textbooks does not receive enough attention in policy and research. This article, drawing from a multiple-case study of 10 teachers, using classroom observations and teacher interviews, explores different ways in which teachers use the Math-Magic mathematics textbook in Delhi’s government primary schools. The findings demonstrate heterogeneity in the ways in which teachers use textbooks, which are the dominant teaching resource in these schools. Teachers use different degrees of agency in textbook use—from avoiding the textbooks to designing their lessons. These are influenced by their views about the textbooks, as well as their institutional realities. Finally, this heterogeneity offers a useful approach to understanding textbooks, and their relevance to teaching beyond being viewed as teaching scripts.