This paper reflects on the project for the creation of teaching scenarios for the curricular Interdisciplinary Topic of Sustainable Development, which addressed a wide variety of subjects in Croatian primary and secondary schools. The paper intends to provide insight into potentially replicable approaches for the creation of teaching resources in similar contexts. The paper aims to identify (1) the project’s approaches that stimulated interdisciplinary collaboration during the creation of the teaching scenarios, and (2) the project’s approaches that could facilitate the adoption of the teaching scenarios by a wide variety of subject teachers. The approaches are explored through observation and reflection by the author, who was the key expert and development leader for the teaching scenarios. The interdisciplinary creation is found to be stimulated by creating conditions for authors to explore sustainable development with an awareness of their subject’s important role in it while paying attention to team relationships, processes, and results, including in online collaboration spaces. The teaching scenarios are found to be more likely to support a multidisciplinary type of implementation than an interdisciplinary one due to teaching activities mostly being not integrated enough to enable team teaching. This, however, allows more enthusiastic individual teachers to use the activities autonomously. The scenario adoption may be supported by the efficient simultaneous addressing of subject outcomes and sustainable development outcomes, by the adaptability of teaching activities, and by the connection between scenario topics and real life, including the life of the school community and wider communities.