This study examines implementation factors of a pioneering plurilingual policy designed to foster language development in early childhood education and care in Luxembourg. Using a mixed-method design, combining qualitative expert interviews and a quantitative survey, it offers insights from both policy- and practice-level perspectives on factors that may facilitate or hinder policy implementation. The study shows horizontal and vertical sectorial disparities among ministerial stakeholders at the policy level, and disparities between different organizational forms at the practice level. These multi-level variations highlight the complex nature of policy implementation and the factors acting as facilitators or barriers to its success. This research suggests (1) a more tailored approach to policy implementation to consider organizational diversity; (2) a more epistemological framework for policy guidelines to avoid ambiguities between policy and practice; and (3) promotion of continuous professional development and exchange groups among different practice-level sectors to facilitate policy implementation in practice.