Despite the prevalence of the spacing effect in the psychological literature, the impact of lesson timing has not yet been fully explored in real classrooms. The current study examined whether spacing could improve long-term retention of both factual and critical thinking curriculum-based teaching materials for children. Students 9 to 12 years old were taught to judge the credibility of websites in either three consecutive days of lessons or one lesson per week. Thirty-five days after the final lesson, students were tested on factual knowledge and applied their knowledge to evaluating a new website. Students in the spaced condition remembered more facts from the lessons and were better able to explain their website ratings than students in the massed group.