Her research expertise is in the area of the transition to school, including kindergarten and integrated early years services such as Toronto First Duty and Peel Best Start. She has carried out extensive research on the role of parents in early education and family literacy in diverse populations. Pelletier is a former kindergarten and Grade 1 teacher and is a council member for the College of Early Childhood Educators. She teaches and supervises graduate students in Developmental Psychology and Education and in the two-year MA in Child Study and Education teacher education program at the Institute of Child Study.