Abstract 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 safety of water lentil powder as a novel food (NF) pursuant to Regulation (EU) 2015/2283. Water lentils refer to aquatic plants belonging to the Araceae family and represented by five genera (Lemna, Wolffia, Wolffiella, Landoltia and Spirodela). The NF is thermally washed and dried water lentils, which are produced as a polyculture crop consisting of species from the Lemna genus (70–100%) and the Wolffia genus (0–30%). The main constituents of the NF are protein, fibre and fat. The Panel notes that the concentration of trace elements and contaminants in the NF is highly dependent on the conditions of cultivation of the plant and the fertiliser composition. The NF is expected to be stable and to comply with the specifications during the suggested shelf life. The NF is intended for human consumption as a food ingredient in herbs, spices and seasonings, sauces, soups and broths, protein products, dietary food for weight control and as a food supplement. The target population is the general population, except for food supplements which are exclusively intended for consumption by adults. The Panel considers that based on the composition of the NF and the proposed intended uses, the NF is not nutritionally disadvantageous, except for the concerns regarding intake of manganese from the NF. No adverse effect was observed in the submitted 90‐day subchronic study, at the highest dose, 1,000 mg/kg body weight (bw) per day of NF. The Panel considers that, based on the protein concentration, the consumption of the NF may trigger allergic reactions. The Panel concluded that an increase in manganese intake from the NF used as food ingredient or food supplements is of safety concern and the safety of the NF cannot be established.