The informal food sector plays a pivotal role in the livelihoods and food security of low- and middle-income countries, yet it remains underexplored compared to its formal counterpart. This meta-study synthesises existing research to identify innovations within the informal food sector that enhance inclusivity, efficiency, and sustainability for marginalised actors such as small farmers and traders. Focusing on both disruptive and sustaining innovations, the study examines their origins, adoption patterns, and impacts on food systems. Disruptive innovations, such as mobile payment technologies, have reduced transaction costs and improved market access, while sustaining innovations, like new contracting methods, have optimized traditional processes. The analysis highlights the unique challenges and opportunities in the informal sector, including fragmented supply chains, diverse actors, and limited regulatory oversight. Additionally, the study identifies critical knowledge gaps, emphasizing the need for further research to understand how innovations diffuse through informal networks and their broader socioeconomic and environmental implications. By addressing these gaps, policymakers and practitioners can better design interventions that build on informal sector innovations, fostering economic growth, rural development, and food system resilience.