(1) Background: The growing number of banking entities linked to the field of banking since the 1980s requires a preliminary classification of this sector in order to identify the main stylized facts of this wide conglomerate of institutions oriented to financial sustainability as well as the establishment of an effective differentiation that can objectively distinguish the different types of institutions operating in this subfield of finance. The objective of this research is to obtain a frame of reference by determining the main defining characteristics of these entities and their differentiating elements, by verifying, on an analytical basis, the ways in which they provide a social service in the pursuit of financial inclusion. (2) Methods: A double methodological perspective is used jointly: Factor Analysis and Cluster Analysis. (3) Results: It was possible to delimit two significant groups: Ethical Banks per se and Poverty Alleviation Banks, defining their main differences and analogies. (4) The taxonomy conducted revealed that Ethical Banks per se are primarily established in developed countries, while Poverty Alleviation Banks focus their actions on developing nations. Based on this classification, we establish a series of practical policies that support the future deployment of sustainable banking.