The belief that mathematics ability is a fixed trait is particularly common and may be a key reason for many students' disinterest and underperformance in mathematics. This study investigates how mathematics teaching practices might contribute to students' beliefs about mathematics ability being a fixed or malleable trait (mindset). Through a synthesis of existing literature and an analysis of data from classroom observations, this article presents a framework of teaching practices and identifies how varying implementations of these practices can be classified along a continuum from conveying fixed-mindset messages to conveying growth-mindset messages related to mathematics ability.