The attitudes of people aged under 60 towards ageing have important links with well-being outcomes. Despite this, there has been little consideration of how attitudes to ageing are measured, and how relationships between attitudes and well-being develop and are moderated by age, particularly in non-Western populations. The aims of this thesis were, therefore, to translate, adapt, and psychometrically assess selected measures of attitudes to ageing, and assess how attitudes to ageing are associated with well-being outcomes in an Eastern (Malay) population aged from 18-60 years. These aims were achieved through four empirical studies. Study 1 was a systematic review of the psychometric properties of measures of attitudes to ageing among people younger than 60. Twenty-one articles relating to ten different measures in ten languages were identified. In studies 2 and 3, two of these measures, namely the Anxiety about Ageing Scale (AAS: reflecting concerns/ anxiety about growing older) and Reactions to Ageing Questionnaire (RAQ: reflecting anticipations about future ageing), were translated and culturally adapted for an adult Malay population. The psychometric properties of the AAS and the RAQ, and the effects of age, gender, and education were also examined in a sample of 911 Malay participants aged 18-60. Only slight modifications were required to the original four-factor structure of the AAS. Of the four factors identified from the Malay RAQ (M-RAQ), three were similar to those found in Western populations, and one ('Family and Religion') was new to this population. A core set of items that worked well across several cultural groups was also identified for each scale. For both scales, more negative attitudes to ageing were generally found in younger and female participants. Those with lower levels of education had more negative attitudes to ageing on the total score and two subscales of the Malay AAS (M-AAS), but there were no effect of education on the M-RAQ or its subscales. Study 4 examined the moderating effects of age on the potential relationships between attitudes to ageing and well-being outcomes in the same Malay population. More negative attitudes to ageing were linked to lower levels of well-being and life-satisfaction. Age moderated the links between the M-AAS and well-being and life satisfaction, with a stronger effect identified in younger compared to older participants. No moderating effects of age were seen when using the M-RAQ. A number of important conclusions can be drawn from the findings of this thesis: First, there are a number of conceptual differences in the ways that attitudes to ageing have been measured in younger adults. Second, the M-AAS and the M-RAQ provide good measures of the attitude constructs 'current concerns about growing older' and 'anticipations about future ageing', achieving satisfactory psychometric properties in Malay adults younger than 60. Third, some items assessing attitudes to ageing work well across a variety of cultures, whereas others may be more culturally-specific. Finally, there is a moderating effect of age on the links between the M-AAS and well-being outcomes, showing that these relationships are stronger in younger than older people. These findings illustrate the importance of selecting measures of attitudes to ageing that are culturally appropriate, and which capture the specific level and type of attitudinal construct. They also suggest that interventions aimed at enhancing positive attitudes to ageing would be best targeted at reducing concerns and anxiety to ageing in younger adults.