The intent of this thesis was to better understand the educative role of group exercise instructors, and how this role is approached when working with older exercisers. Data were collected using textual analysis, observations of instructors’ teachings in group exercise classes, semi-structured interviews with instructors and older exercisers, and go-alongs with older exercisers. This thesis is comprised of four papers (three journal articles and one book chapter). The first paper reports findings from a scoping review and elucidates that the educative role of exercise instructors is vital but under researched. Paper 2, a book chapter, reports findings from a qualitative content analysis of eight curricula used to train and certify fitness instructors in Canada and the United States. This paper proposes strategically employing compassionate ageism to meet older exercisers’ needs without (re)producing social inequalities in response to finding that the curricula conceive the older body as different from the healthy, supposedly ideal standard. Paper 3, an Institutional Ethnography, provides evidence for some of the ways employers and the aforementioned curricula influence how instructors teach. Paper 3 reports that multi-level teaching may not be enough to foster inclusivity, thus suggesting a greater need for stratification by ability rather than age. Additionally, findings outline some ableist teaching practices, which some instructors resisted by drawing on their competence to employ teaching methods respecting exercisers’ agency. Finally, Paper 4 introduces a substantive, grounded theory of age capital, which builds on Bourdieu’s theorizations of cultural capital, as well as Mauss’ habitus and body techniques. Age capital is defined as possessing a gerontological embodied competence, or cognitive and embodied knowledge of the socio-cultural practices throughout one’s life course. Collectively, this thesis provides several recommendations for teaching group exercise in a manner that fosters more inclusive classes for older adults. / Thesis / Doctor of Philosophy (PhD) / The key goals of this research were to understand how fitness instructors’ training might influence how instructors teach in their group exercise classes, learn how and what fitness instructors teach, and identify how instructors’ teaching is (or should be) different with older exercisers. I found that fitness instructors are important to group exercise classes, as they bring people together and teach people how to exercise safely. It is also especially important that instructors have special training to work with older people, but there is a lack of consistency in the training of exercise instructors and instructors received mixed messages about ageism in their training. This could reinforce the idea that older persons lose abilities as they age and result in a one-size fits all way of teaching that fails to include older exercisers’ diverse abilities. This research suggests ways instructors can be better trained to relate to older exercisers.