Purpose: The purpose of this study is to extend the current knowledge of curriculum developments in international business and marketing curricula. Integrating sustainability into business and marketing curricula of the universities are widely debated in previous literature. Sustainability is a global phenomenon; however, curriculum development projects aimed at integrating sustainability education into international business and marketing curricula are scarce. The study investigates the learning gaps in sustainability education among undergraduates enrolled in an International Marketing course to postulate a series of pedagogical practices, leading to effective integration of sustainability education into the curricula. Design/methodology/approach: Two-phased research method consisting of complementary data collection techniques informed the findings of this study. First, an online survey was conducted among 111 undergraduates enrolled in an International Marketing course. The findings of the survey are used in designing the second phase of data collection performed through a content analysis of essays written by 60 undergraduates evaluating sustainable marketing practices of international firms. Informed by the findings gathered through SPSS- and Nvivo-aided data analysis, this study postulates a series of pedagogical practices. Findings: The study argues that curriculum development projects in integrating sustainability into an existing curriculum in universities should be aimed at bridging undergraduates' learning gaps in sustainability education. The main learning gaps identified in the study reveal that undergraduates find it difficult to view the social function of international business firms from a holistic point of view; critically assess sustainable marketing practices; and articulate futuristic views on sustainable marketing practices. Further, the content analysis revealed three major thematic categories: sustainability from reductionists' perspective, sustainable marketing practices bring nothing "but good for businesses", ambivalent about the future success of sustainable marketing practices. Triggered by these learning gaps, thematic categories and the theoretical underpinnings of Rusinko's (2010) matrix for integrating sustainability education, the study offers a set of practical pedagogical guidelines to incorporate sustainability education into curricula. Research limitations/implications: The study is limited to exploring undergraduate student perspectives, and it would be worthwhile if educators' perspectives are explored in future studies. The findings could be further improved by conducting a cross-sectional study across several business disciplines. Practical implications: Based on the findings of the study, a set of guidelines for developing a pedagogical plan to incorporate sustainable education into curricula is presented. Originality/value: Educators argue that successful curriculum development projects aiming at integrating sustainability into existing curricula should be aligned with the structure of the existing curricula, and those new pedagogical practices in integrating sustainability into existing curricula should be built on students' learning gaps in sustainability education. To this end, this study examined undergraduates' learning gaps in sustainability education and postulated pedagogical practices toward integrating sustainability education into an existing curriculum of international marketing.