Background: The inability to assign a protein content claim (PCC) to plant foods may impede efforts from Canada’s Food Guide to increase consumption of plant protein. A systematic application of PCC frameworks from other regions to Canadian nutrition surveillance data would be useful to model potential effects of PCC regulations on the nutrient intake, protein quality, and corrected protein intake of diets. Methods: Plant food groups that qualified for a PCC within the Canadian Nutrient File according to regulations from Canada, the United States (US), Australia and New Zealand (ANZ), and the European Union (EU) were identified. Adults (≥19 years) (n = 11,817) from The Canadian Community Health Survey (2015) who consumed ≥1 plant food qualifying for a PCC in each region were allocated to the corresponding PCC group. The effects of Canadian PCC regulations on the protein quantity, quality (Digestible Indispensable Amino Acid Score, DIAAS), and nutrient intakes of Canadian diets in adults were compared to PCC groups from other regions. Results: Substantially more individuals were consumers of plant-based protein foods, using the ANZ and the EU PCC regulations, compared to the Canadian and US PCC groups. There were no differences in uncorrected protein intake across PCC groups. All DIAAS values were >0.94, and corrected protein intakes were >74–89 g/day or 16%E across PCC groups. Non-consumers of plant foods eligible for a PCC had corrected protein intakes that ranged between 68 and 78 g/d or 17%E. Generally, consumers of plant foods eligible for a PCC in the US, ANZ, and EU, or both Canada and the US/ANZ/EU, had higher intakes of positive nutrients, such as fibre, calcium, iron, magnesium, and zinc (p < 0.05) and lower saturated fat. Conclusions: Less restrictive regulatory frameworks for PCC used in ANZ and the EU did not substantially affect protein intake or the protein quality of Canadian diets in adults. These results suggest that more inclusive regulatory frameworks for protein PCCs could support increased intake of food sources of plant proteins in alignment with Canada’s Food Guide.