The largest generation on earth, Generation Z, holds substantial market power. They were born onto a planet that is overheating, in a society characterized by high growth and technological advancements at an accelerated speed, and are inheriting substantial sustainability, socio-economic, and climate change challenges. Given this, they are aware of the importance of incorporating sustainability into their purchasing decisions. Since the contemporary topic of sustainable decision-making of Gen Z is still in its nascent stage, this research further investigates the process an individual goes through when deciding what aspects guide them in decisions as well as what could possibly hinder Gen Z to turn sustainable purchasing intentions into behavior. Data was collected through semi-structured interviews with individuals of Europe’s Gen Z cohort and subsequently processed using thematic analysis. Based on the EBM customer decision model, the information integration theory, and the green intention-behavior gap model, three categories focusing on rational, value-based, and intentional themes were derived. Results show that Gen Z goes through a complex decision process which is based on their strongly held values. Their intention to act sustainably is prevalent throughout the process, where they often combat internalized consumerism, search for authentic and honest information, rely on family, friends, their sustainability education and knowledge, their favorite brands, and are skeptical about claims made by companies. Even if individuals desire to purchase sustainably all the time, price, availability and accessibility, missing aesthetics as well as skepticism and the lack of transparency and regulations in terms of sustainability terminology hinders them to turn intentions into actions.