This is the executive summary for the policy brief, "Expanding the Definition of Student Success under ESSA: Opportunities to Advance Social-Emotional Mindsets, Skills, and Habits for Today's Students." Signed into law on December 10, 2015, the Every Student Succeeds Act (ESSA) presents education leaders with a unique opportunity to expand the definition of student success. Compared to the No Child Left Behind (NCLB) Act, ESSA empowers states to make more of the critical decisions related to accountability, school improvement, education spending, and public reporting. Although regulations to guide the new law's implementation are still being finalized, ESSA clearly requires states to broaden the concept of school quality and student success to include factors beyond test scores and graduation rates, suggesting that education systems need to take a more holistic approach to preparing students for college and career. Meanwhile, compelling evidence on the importance of certain social-emotional or intrapersonal and interpersonal competencies has emerged in recent years. TransformEd refers to these competencies as Mindsets, Essential Skills, and Habits (or MESH). The policy brief describes three recommendations in greater detail and outlines how these recommendations align with the provisions of ESSA. It also provides an examCople of one school system--the CORE Districts--that has already begun to act on these recommendations to advance students' development of the mindsets, essential skills, and habits that support college and career success. [For the full report, see ED605420.]