We previously demonstrated that spatial context is a powerful reminder that can trigger memory updating (Hupbach, Hardt, Gomez, & Nadel in Learning & Memory, 15, 574-579 2008). In the present study, we asked whether the familiarity of the spatial context modulates the role of spatial context as a reminder. Since context familiarity can be easily manipulated in children, we chose 5-year-olds as study participants. In two experiments, we demonstrated robust memory-updating effects in children. Spatial context triggered incorporation of new information into old memories only when the context was unfamiliar. In highly familiar spatial environments (children's homes), spatial context did not initiate memory updating. Other reminders (the experimenter and a reminder question) became highly effective in familiar contexts. These findings shed further light on the specific conditions that trigger memory updating and support the view that the mechanisms underlying it are similar in children and adults.