The global climate crisis and the substantial greenhouse gas emissions associated with the food industry necessitate the flourishing of green initiatives in this sector. As a response, new food sources (NFS) have emerged as a means to shift consumption behaviors and enhance sustainability. However, NFS companies, often characterized by limited resources and expansion challenges, face difficulties in achieving sustainable growth. This research has the purpose to investigate the necessary capabilities for successful sustainable expansion within the NFS sector and develop a comprehensive framework that maps these capabilities to different stages of expansion. Through a multiple case study approach, encompassing 21 interviews conducted within the NFS sector, this study identifies five stages of sustainability work that act as drivers for sustainable expansion. Moreover, eight categories of capabilities crucial for achieving sustainable expansion are identified and ranked in a progressive manner, from fundamental to competitive advantage. Subsequently, the study establishes a framework that links the five stages of sustainable expansion with the corresponding capabilities, providing a practical guide for NFS companies seeking to pursue sustainable growth. This research contributes to the understanding of the NFS sector by uncovering key success factors for sustainable expansion. The findings offer valuable insights for NFS companies and stakeholders, informing strategic decision-making and fostering sustainable practices in the food industry.