"Multitier systems of support" (MTSS) are widely understood as an evidence-based framework for coordinating integrated delivery of a continuum of layered services to support students' development. Traditionally, MTSS includes three tiers. Tier 1 refers to universal supports that are system-, school-, or classwide; tier 2 includes targeted services beyond general supports; and tier 3 and beyond provide intensive and sustained individualized services. Although equity is identified as a feature or outcome of MTSS, particularly when considered in the context of prevention of racial disproportionality through MTSS, the authors propose that equity should be more foundational to MTSS design, implementation, and evaluation in order to advance social justice and protect student rights. As such, this "Equity by Design" brief introduces an expanded conceptualization of equity-centered MTSS, describes its key features, provides guided questions to evaluate an existing MTSS system, and identifies resources to support this work.