People with narcolepsy consistently report diminished memory function attributable to the disorder, however, objective evaluations of memory performance in this clinical group remain inconclusive. Previous evaluations of these subjective experiences have been primarily anecdotal with subjects required to provide global assessments of their memory function. The present study aimed to evaluate subjective assessments of memory dysfunction more extensively comparing responses by narcoleptics, subjects experiencing excessive daytime sleepiness, and controls, on the Metamemory in Adulthood (MIA) questionnaire. The results of the study indicate that subjects with narcolepsy have lower self efficacy for memory performance than either of the comparison groups, despite there being no significant difference between groups in relation to knowledge based aspects of memory functioning. This lowered self efficacy in narcolepsy is expressed through increased anxiety about memory function, decreased evaluations of memory capacity and increased perceptions of memory decline in relation to the comparison groups. It is argued that the negative cognitive self evaluations of narcoleptics potentially arise as a consequence of global psychosocial adjustment difficulties.