Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on 3′‐sialyllactose (3′‐SL) sodium salt as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF is mainly composed of the human‐identical milk oligosaccharide (HiMO) 3′‐SL (sodium salt), but it also contains sialic acid, d‐glucose, d‐lactose, 3′‐sialyllactulose and 6′‐sialyllactose sodium salts and a small fraction of other related saccharides. The NF is produced by fermentation by a genetically modified strain (Escherichia coli NEO3) of E. coli W (ATCC 9637). The information provided on the identity, manufacturing process, composition and specifications of the NF does not raise safety concerns. The applicant intends to add the NF to a variety of foods, including infant formula and follow‐on formula, food for special medical purposes and food supplements (FS). The target population is the general population. The applicant applies for the same uses and use levels as already assessed for 3′‐SL sodium salt produced by a genetically modified strain of E. coli K‐12 DH1, with the exception for the use in FS, which is proposed to be higher (from 0.5 to 1.0 g/day) in individuals from 3 years of age. Since the NF as a food ingredient would be consumed at the same extent as the already assessed 3′‐SL sodium salt, no new estimates of the intakes have been carried out. The Panel notes that the maximum daily intake of 3′‐SL from the proposed use of the NF in FS for individuals from 3 years of age (1.0 g/day) is lower than the estimated highest mean daily intake of 3′‐SL in breastfed infants. FS are not intended to be used if other sources of 3′‐SL are consumed on the same day. The Panel concludes that the NF is safe under the proposed conditions of use.