Prior research indicates that, in some circumstances, reminders may facilitate prospective remembering. However, it remains unclear whether this effect is dependent on the initiation source (self vs. external), whether it is moderated by task type (event vs. time based), or whether the provision of standardized reminders particularly benefits older adults. In the current study, young (n = 48) and older adults (n = 47) were tested on a laboratory-based prospective memory task in which they encountered three counterbalanced reminder conditions: no reminders, self-initiated reminders, and experimenter-initiated reminders. The results indicated that while the provision of reminders enhanced prospective memory performance, no difference was seen between self-initiated and experimenter-initiated reminder conditions, nor was there any interaction with age or prospective memory type (event vs. time based). These data support the role of both self- and externally generated external reminders as an aid to prospective remembering. However, the absence of any interaction with age is not consistent with theoretical models of ageing that consider the provision of such reminders to reduce strategic demands (or increase automatic processing).