In Buddhist Studies, forms of Buddhism their practitioners call “traditional” are often excluded from research, stereotyped in negative ways, or deemed modern. This practice affects two sub-fields of Buddhist Studies: studies of contemporary Buddhism and of Buddhist social engagement. Overlooking traditional-identified forms of Buddhism when studying contemporary Buddhism or categorizing them as modern has led to not exploring their histories, features, and activities. Overlooking traditionalist Buddhists’ socially beneficial activities has led to portraying modernists’ engagement as all of Buddhists’ engagement and not identifying features of engagement particular to traditionalists. Both sub-fields thus produce incomplete pictures of today’s Buddhisms and Buddhists. To address these gaps, ethnographic and textual research was undertaken on the Foundation for the Preservation of the Mahayana Tradition (FPMT), a large transnational organization that describes its Buddhism as traditional. Research determined the bases on which people in FPMT label their Buddhism “traditional” and used these to develop a stipulative definition of “traditional Buddhism” that avoids stereotypes and enables scholars to distinguish traditional from other forms of Buddhism. Adding a category for “traditional Buddhism” to Buddhist Studies, paralleling “modern Buddhism” and “postmodern Buddhism,” will make understudied types of Buddhism more visible, increasing research on them and improving understanding. The dissertation then addresses scholars’ view that social engagement is undertaken only by modernist Buddhists by showing that FPMT is socially engaged and describing the impetus, nature, and features of its engagement. It then posits that a category of “traditionalist social engagement,” with particular characteristics, can usefully be added to the study of engaged Buddhism. The dissertation thus finds its place within scholarship on contemporary Buddhism and Buddhist social engagement, adding data and advancing theoretical discussions in these areas as well as contributing new research on FPMT, an influential and globally active, but little-studied, Buddhist organization.