With advances in technology and medicine, people are living longer, but this does not guarantee that they are living well. Given the increasing proportion of older adults in the global population, the United Nations has declared the years 2021-2030 as the Decade of Healthy Ageing - an initiative focused on improving quality of life in older age, with cognition as a major pillar. Consequently, much of the research on cognitive aging has focused on interventions that may ameliorate the effects of age-related cognitive decline. Cognitive training has become one of the most prominent candidates under investigation, though studies have yielded mixed findings for this type of intervention to promote improvements in (transfer to) everyday tasks. As core executive functions (EFs; cognitive flexibility, inhibitory control, working memory [WM]) are crucial for everyday functioning and are fundamental building blocks for other cognitive processes, this research program investigated the potential of cognitive training targeting core EFs in facilitating improvements in cognitive, subjective, and neural outcomes for older adults. Specifically, the five studies within this research program address gaps and equivocal findings in the cognitive training literature pertaining to: i) the uncertainty of training-related transfer and conditions that may promote transfer effects (Studies 1 and 2), ii) the lack of empirical evidence directly comparing the efficacy of multidomain versus single-domain training - particularly including subjective outcomes which have important implications for healthy aging (e.g., self-esteem, attitudes toward one's own aging journey) (Study 3), iii) older adults' experiences and preferences regarding cognitive training and what can be done to encourage long-term engagement (Study 4), and iv) the uncertainty surrounding the potential for cognitive training to induce neural changes (Study 5). [...]