Although commercially produced complementary foods (CPCFs) are increasingly sold throughout Southeast Asia, concerns have been raised about CPCFs nutritional quality, labelling practices and the strength and scope of national CPCF regulations. The Consortium for Improving Complementary Foods in Southeast Asia (COMMIT), composed of UN agencies and civil society organizations, was formed to assess the nutrient gap in the diets of young children and the consumer, product and policy landscapes for CPCFs in seven Southeast Asian countries. Results from a nutrient gap assessment indicate that the diets of children aged 6–23 months are suboptimal and deficient in micronutrients. A consumer survey revealed that caretakers commonly use CPCFs, are conscious of the importance of nutrition and are influenced by label claims. Results from a CPCF benchmarking showed that many products sold in Southeast Asia contained added sugar or sweeteners, had a high total sugar and/or high sodium content and that no CPCF product adhered to all recommended labelling practices. Further, a legal review of national binding legal measures relevant to CPCFs showed minimal alignment with available global guidance. Urgent actions are necessary to strengthen national regulations related to CPCF nutrient composition and labelling practices. To speed progress, COMMIT developed a compendium of existing standards and global guidance to help countries align their national regulations with CPCF composition, labelling and production recommendations. Advocacy to garner public support for new or improved CPCF regulations, as well as strong government monitoring and enforcement of regulations, is crucial to support efforts to safeguard and improve the diets of older infants and young children in Southeast Asia.