Most professional development opportunities for early childhood teachers are offered as face-to-face sessions (in various formats, including workshops, coaching, and college courses), tailored for teachers in traditional school- or center-based child care, offered during a traditional academic year, or during summer, or on professional development days when children do not attend (Sheridan, Banzer, Pradzinski, & Wen, 2020). These professional development sessions often involve lecturing, reflective practice, peer collaboration, and coaching/mentoring for individual feedback. Notably, none of these models fully meet the needs of the current early childhood workforce. Early childhood educators indicate that time, location, and cost are factors limiting access to professional development opportunities. Online professional development has the potential to overcome some of these barriers through providing access, relevance, and content level specificity that early childhood educators seek. This review presents one of the nation's first online professional development models that targets early math teaching and learning, "Early Math Counts." Results of an Illinois-based evaluation study published in the journal of "Early Education and Development" to test the effectiveness of this early math professional development model are also shared.