Fish is especially rich in essential omega-3 long-chain polyunsaturated fatty acids and micronutrients, including bioavailable calcium, iron and zinc. Fish features prominently in the diet of most, especially poor, Zambians. Despite this, its significance in the diet of women and children in the first 1,000 days is not well understood. Our current knowledge of the nutrient content of commonly consumed fish species in Zambia is synthesised. The importance of fish in food and nutrition security of rural and urban households and the impact of intra-household distribution on nutrient intake from fish, especially among pregnant and lactating women and children 6–23 months of age, are explored in this article. Key knowledge gaps are identified, and research priorities are highlighted. Recommendations are provided on policy, communications and technological initiatives to maximise the role fish can play in the First 1000 Most Critical Days Programme in Zambia.