In the NOVA classification system, descriptive criteria are used to assign foods to one of four groups based on processing-related criteria. Although NOVA is widely used, its robustness and functionality remain largely unexplored. We determined whether this system leads to consistent food assignments by users. French food and nutrition specialists completed an online survey in which they assigned foods to NOVA groups. The survey comprised two lists: one with 120 marketed food products with ingredient information and one with 111 generic food items without ingredient information. We quantified assignment consistency among evaluators using Fleiss’ κ (range: 0–1, where 1 = 100% agreement). Fleiss’ κ was 0.32 and 0.34 for the marketed foods (n = 159 evaluators) and generic foods (n = 177 evaluators), respectively. The consistency of the assignments, as assessed by Fleiss’ κ, was 0.32 (commercial foods) and 0.34 (generic foods). Clusters of foods with similar assignment distributions were defined by hierarchical ascending classification. Among the 120 commercial foods, one cluster contained 90 foods that were predominantly assigned to NOVA4 (91% of the assignments) and, among the 111 generic foods, three clusters contained foods that were predominantly assigned to NOVA 1 (79% of the assignments), NOVA2 (75%) and NOVA4 (70%), respectively. Assignments were particularly heterogeneous for 30 commercial and 28 generic foods (25% of the total in both cases). Although assignments were more consistent for some foods than others, overall consistency among evaluators was low, even when ingredient information was available. These results suggest current NOVA criteria do not allow for robust and functional food assignments.