Research has demonstrated that negative ageing stereotypes can have detrimental effects on the cognitive test performance of older adults. Age-based stereotype threat (ABST) can pose serious risks in the cognitive assessment of older adults, especially in the context of early identification of cognitive impairment and dementia. To date, research in this field has predominantly focussed on the performance decrements older adults experience when faced with negative ageing stereotypes during cognitive assessment. Less focus has been placed on investigating whether health practitioners recognise the potential influence of ABST on the cognitive test performance of older adults and ways in which its negative effects can be reduced. Comprised of three studies, the broad objectives of this thesis were to advance understanding of health practitioner beliefs regarding the impact of ABST in clinical practice and ways to alleviate the impact of ABST on older adults’ cognitive test performance.