<p>Mindsets, beliefs about whether abilities can improve, are thought to be important determinants of psychological processes and outcomes. However, the traditional distinction between fixed (unable to change) and growth (able to change) mindsets leaves unexplored a related set of beliefs concerning whether it is possible to change the effort or speed at which growth happens. To create a new measure of these beliefs—which we refer to as Growth Rate Orientation (GRO) beliefs—in Study 1 (<i>N</i> = 260), we conducted an exploratory factor analysis then, in Study 2 (<i>N</i> = 239), conducted a confirmatory factor analysis and examined both convergent and divergent validity. Results supported a three-factor solution, separating growth-rate (e.g., I can change the speed at which I grow), growth-effort (e.g., I can change how much effort growth requires), and fixed-change (e.g., I cannot change how easily or how quickly I grow) beliefs from each other and from classic fixed/growth mindset measures (.26 &lt;|<i>r</i>|s &lt; .66). Additionally, results suggested that GRO beliefs, particularly the growth-effort and fixed-change beliefs, predicted related outcomes (goal orientations and self-handicapping) as well as or even slightly better than traditional mindset measures. Implications regarding theory and measurement of mindsets are discussed.</p>