In this paper we report on a survey study of teachers' perceptions of how mathematics textbooks, including broadly student books, teacher manuals, and exercise books, facilitate or hinder teachers' teaching in Shanghai educational settings. For the study we established a conceptual framework about teachers' teaching, partly drawing on Shulman's model of pedagogical reasoning and action of teachers. The data were collected from a stratified random sample of 133 mathematics teachers in 13 secondary schools through a questionnaire, and follow-up interviews with 24 of them. The results revealed the following: the textbooks were highly regarded and used by the Shanghai mathematics teachers as facilitators rather than barriers for their teaching and instructional change, and the facilitation was most evident in the process of transformation and comprehension, and least evident in evaluation in teachers' pedagogical reasoning and action; compared with student books and exercise books, teacher manuals played a larger facilitating role in teachers' teaching; and finally, compared with teacher characteristics, school characteristics had a greater influence on the extent to which textbooks played a role of facilitation or hindrance for teachers' instructional practice. Implications and suggestions are given at the end of the paper.