Introduction: The source of protein in diets (plant vs animal) is central to their eco-environmental sustainability. Plant protein intake, which is favorably associated with the intake of many nutrients, has been shown to be a strong, robust marker of a healthy diet. However, it remains unclear if this association could also be explained by a higher dietary diversity, which usually favors nutrient adequacy. It is unknown if the intake of plant protein vs animal protein could relate to dietary diversity. Objectives: Our main objective was to determine if the relation between plant protein intake and nutritional adequacy could be explained, at least in part, by the association with dietary diversity. Method / Design: We used data from 1330 adults participating in the French Nutrition and Health Survey (ENNS, 2006-2007). We evaluated the plant and animal protein sources and intakes. Using global, integrative approaches, we assessed nutrient adequacy (using the probabilistic PANDiet scoring system) and dietary diversity (using a 100-point score that account for the number of consumed subgroups in each food group).We used linear multivariate modelling with adjustment for potential confounders. Results: As expected, plant, but not animal, protein intakes were significantly associated with the PANDiet score. We found a positive association between dietary diversity and nutrient adequacy, and between dietary diversity and plant protein intakes, but not total of animal protein. In a full model adjusted for potential confounders (total energy, energy density, sex, income, occupational status, educational level, region and smoking status), nutrient adequacy was positively associated with dietary diversity (β = 0.13) and plant (β = 0.27) and animal (β = 0.05) protein intakes. Conclusions: Plant protein intake is associated with nutrient adequacy of the diet independent of the relative dietary diversity of French adults.