Multi-tiered System of Supports (MTSS) is a framework in which educators intensify intervention and instructional supports in response to student data. Response to Intervention (RTI), is one of the most prevalent forms of MTSS utilized in schools and is commonly used to identify students with disabilities, including culturally and linguistically diverse learners who are often disproportionately represented in special education. Culturally and linguistically relevant RTI holds promise for promoting equitable outcomes for diverse students, including Dual Language Learners (DLL). A case study design was used to explore the actions and beliefs of an elementary mathematics teacher as she sought to meet the needs of a diverse group of learners. Findings illustrate examples of individual and collective teacher efficacy, understanding student progress, valuing student voice and discourse, believing in her CLD students’ ability to succeed, and working towards a larger shared vision at the school. Implications for culturally and linguistically relevant tiered mathematics instruction are discussed.