Prospective memory (PM) refers to a person’s ability to remember to do something in the future. It is a complex behaviour that is essential for the daily functioning of young and old alike. Despite its importance in everyday life, few studies have sought to examine the role of personality on PM performance using a multi-trait multi-method approach in young adults. The current study aimed to investigate the differential roles of the Big 5 personality traits on event- and time-based PM performance using multiple measurement methods. In addition, the study aimed to add to the current PM and personality literature by addressing several of the identified methodological limitations of the literature as outlined by Uttl and colleagues (2013). Results demonstrated few strong relationships between PM subtypes (event and time-based) performance indicators, though performance on the lab-based event-based PM task was stronger than on the lab-based time-based PM task even after controlling for ongoing task performance. Participants were also found to perform better on lab-based rather than naturalistic PM tasks. Naturalistic and self-report PM measures were significantly related to each other, but not to lab-based PM. Regarding personality, the relationship between specific personality traits and PM performance differed depending on the PM subtype and/or measurement method being investigated with conscientiousness, memory aid strategy use, and substance use engagement being found to best predict self-reported PM errors in daily life. The current study demonstrated that each PM measurement method taps into different aspects of behavioural and cognitive functioning. Without the use of all three measurement methods, whilst also considering the individuality of the client, researchers and clinicians may be doing a disservice to individuals with true PM difficulties as they may overlook important factors contributing to their poorer performance. / Graduate