The EFSA NDA Panel was asked to deliver an opinion on Lemna minor and Lemna gibba whole plant material as a novel food (NF) pursuant to Regulation (EU) 2015/2283. Lemna minor and Lemna gibba are aquatic plants commonly named water lentils. The NF is produced by cultivation of Lemna minor and Lemna gibba plants, washing with water and heat treatment. The main constituents of the NF are water, protein and fibre. 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 intended to be used as a vegetable, similar to other leafy vegetables. The target population is the general population. The Panel considers that, with the exception of concerns related to the manganese intake, taking into account the composition of the NF and the proposed conditions of use, the consumption of the NF is not nutritionally disadvantageous. The Panel considers that the risk that the consumption of the NF may trigger allergic reactions in humans is low. The Panel concludes that the NF, in consideration of its proposed uses and the concentration of manganese as compared to the normally present concentration of manganese in other leafy vegetables, may be of safety concern, therefore, the safety of the NF cannot currently be established.