Families of children with cancer are confronted with unexpected out-of-pocket expenses and productivity costs associated with the diagnosis. One productivity cost that falls on children is the impact of cancer on children’s school attendance, performance, and activities (eg, play, friendships, and socialization). Nested within the Childhood Cancer Cost Study, this qualitative descriptive study used convenience sampling to recruit and interview parents of children newly diagnosed with cancer. Content analysis techniques were used to inductively descriptive the semistructured interview data. Sixty-six parents of 65 children with cancer and of 73 siblings participated. The most commonly reported productivity loss in children with cancer was school absenteeism mainly due to cancer treatment. Children fell behind their classmates academically and lost important social time with peers. A few siblings also fell behind their peers primarily due to limited parental attention. Parents adopted various strategies to lessen the impact of the diagnosis on their children’s school attendance, performance, and activities. Providing parents with additional resources and support may optimize their children’s academic and social reintegration into school.