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 the extension of use of galacto-oligosaccharides (GOS) as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF (β-GOS) is produced from milk lactose using a β-galactosidase derived from Bifidobacterium bifidum and it is proposed to be used in food for special medical purposes (FSMP). The target population is the general population from 4 years of age onwards. GOS produced according to the same production process are already authorised and included in the EU Union list of novel foods. The applicant stated that the maximum daily intake from the use in FSMP is 8.25 g GOS. GOS are already authorised for use in food supplements up to a daily dose of 16.2 g. FSMP containing GOS are not intended to be used if food supplements containing GOS are consumed on the same day. The information provided on the proposed use levels and anticipated intake does not raise safety concerns. The Panel concludes that the proposed extension of use of GOS in FSMP is safe under the proposed conditions of use.