Since the alignment of the Principles for Responsible Management Education (PRME) for responsible education in management with the SDGs, both launched by the United Nations, the role of Higher Education Institutions (HEI) has become a fundamental pillar for the academic training of future leaders to contribute to the architecture of a sustainable society. However, the academic literature focuses primarily on educational institutional analysis rather than on student outcomes. University students not only reflect a growing awareness of environmental, social, and economic challenges but also display attitudes that influence their personal and professional choices. This paper focuses on a qualitative survey oriented to the attitudes toward sustainability of 129 university marketing students, carried out in two universities in the Iberian Peninsula (University of Almeria—Spain and University of Beira Interior—Portugal). By means of a t-student analysis between the two sample groups, it was analyzed whether the attitudes of students from both universities differ from different perspectives, the personal valuation of the importance of a more sustainable society, the specific integration of sustainability in business, the preference of training toward PRME-oriented educational organizations, or the labor insertion as a worker in sustainable companies. The results of this work can guide academic institutions in the evaluation of their efforts in curricular changes, course redesign, pedagogical proposals, and adjustments in mission and institutional objectives.