Infant/Early Childhood Mental Health Consultation (IECMHC) is a relationship-based, collaborative support designed to improve the capacity of early childhood professionals to promote children's mental health. Social and emotional development is the foundation for success in learning and in life. It begins in children's early relationships with caregivers and is supported by strong partnerships among families, providers, programs, and systems. IECMHC consultants are trained mental health professionals who engage in a variety of promotion, prevention, and intervention activities to build the capacity of early childhood providers to foster social and emotional well-being and development of children and families. A growing body of research has shown IECMHC to be an effective strategy for building the skills of early childhood staff and alleviating their job stress, as well as supporting children and families. This research brief highlights key findings of a 3-year pilot study of the Illinois Model of IECMHC. The study was part of a 5-year comprehensive, coordinated, statewide initiative by The Illinois Children's Mental Health Partnership (ICMHP) to expand IECMHC across multiple systems and settings in Illinois. That initiative began in 2014, after almost two decades of coalition building and advocacy for IECMHC, when a private foundation convened public and private stakeholders to examine early childhood mental health in the state and develop a plan to integrate consultation into early childhood systems throughout Illinois. [This is a report to the Illinois Children's Mental Health Partnership. For the full report, see ED614140.]