<p>Early literacy screening is critical for identifying students at risk for reading difficulties and enabling timely intervention. However, the implementation of new screening tools often encounters significant barriers that hinder effective adoption. This mixed-methods study investigates the barriers and facilitators reported by educators during the early implementation of a new early literacy and language screener. Data from survey (<i>n</i>=694) and focus groups (<i>n</i>=39) were thematically coded using the Consolidated Framework for Implementation Research (CFIR) to identify determinants of successful adoption. Findings revealed four key themes influencing implementation: ease of administration, understanding of the screener, trust in the data, and use of data for instructional decisions. Crosscutting themes included the critical role of reading specialists and the challenges posed by simultaneous curriculum and assessment initiatives. Barriers such as time constraints, technological challenges, and insufficient understanding of language-based subtests were identified, while robust inner-setting supports and effective communication emerged as facilitators. These results underscore the importance of accessible and timely professional development, iterative tool refinement, and strategic leadership in scaling evidence-based practices. Future research should explore longitudinal impacts and strategies to integrate such innovations seamlessly into schools’ instructional ecosystems.</p>