This dissertation investigates how the decision-making processes on sustainability in manufacturing plants are characterized, analyzing process improvement initiatives. Through a multiple-case study with a printing company and an automobile company, it answers the following research questions: how is the (i) breadth, (ii) the depth, (iii) the inclusivity and (iv) the effectiveness of the decision-making process The study aimed at clarifying the theoretical aspects concerning the research theme, comparing the literature suggestions with the characteristics of the decision process observed in companies and presenting discussions based on empirical observation. The research methods are the multiple-case study and the literature review. The literature review included the scoping review and a systematic literature review. The case study sought to apply the protocol in industrial plants of two large companies. Semi-structured interviews were conducted with three employees from each plant, allowing triangulating. Some of the results suggest that the decision-making process close to the Business Case rationale is deep and focused on information processing and narrows the inclusivity to the business-impact stakeholders. Sustainability approaches seem to be broader when progressing in the decision-making steps, varying in breadth and depth during this trajectory. The decision s effectiveness demonstrates a relevant relationship with the data gathering and data analyzing and, also, may be affected by social and organizational factors such as management support, a multidisciplinary decision team and the involvement of employees in the project.