Ongoing expansion of early education services in the United States is often rooted in these programs’ contribution to development that promotes later academic and behavioral competence. Multi-tiered systems of support (MTSS, sometimes referred to as Response to Intervention) represent one increasingly common resource to promote desired outcomes for all children. MTSS requires seasonal screening of all students and progress monitoring of those selected for more intensive intervention. This study explores development and evaluation of measures for these uses, designed specifically to assess the language and early literacy development of 3-year-old children. Results from assessment of 449 children describe measure reliability, growth across three seasonal screenings, development of criterion-referenced benchmarks, and variations in growth for children at different levels of initial performance. Results are discussed in terms of normative versus criterion-referenced standards for building MTSS assessment systems as well as future directions for research, policy, and practice. (author abstract)