In 2015, the Division for Early Childhood of the Council for Exceptional Children released a position statement on leadership in early intervention and early childhood special education (EI/ECSE). Division for Early Childhood emphasized the importance of developing and supporting high-quality leadership within and across all levels of EI/ECSE service systems. Moreover, there was a call for related research because of the paucity of related research in the feld. This cross-sectional survey was designed to address this call. The study expands on an earlier investigation designed to gain an understanding of the competencies needed to be an effective leader at any level of the EI service system under the Individuals with Disabilities Education Act (IDEA), Part C. Using a network-sampling approach, participants in the study described here were recruited from the population of individuals who were engaged, at any level in the EI/ECSE service delivery systems under the IDEA (Part B-619 and Part C). A sample of 820 individuals completed an Internet-based questionnaire. A factor analysis yielded 6 knowledge areas and 5 competency areas considered necessary for effective EI/ECSE leadership. The 6 knowledge areas comprised child development, evidence-based practices, state laws and regulations, family-centered approaches, federal laws and regulations, and group processes. The 5 competency areas comprised Professional Learning, Effective Relationships, Shared Responsibility, Data Use, and Effective Communication. The study results suggest avenues for further examinations of leadership within the EI/ECSE service systems.