This chapter explores the influence of organizational culture and mindset on the implementation and success of sustainability initiatives in banks. Drawing on interviews and organizational theory, it highlights how shared values, language, and beliefs shape attitudes toward sustainability. It investigates how formal and informal narratives are used to mobilize support, legitimize change, or resist transformation. By analyzing cultural archetypes across the four case banks, this chapter reveals that culture is a critical yet often overlooked dimension of structural and strategic alignment. It argues that sustainability risks remaining a peripheral or symbolic exercise without cultural congruence, regardless of its structural embedding.