Methods of making protein-fortified yogurt products are described. The methods may include mixing a casein-containing ingredient with starting milk to make a yogurt milk, where the casein-containing ingredient has a casein-to-whey protein ratio of 82:18 or greater. The yogurt milk may be fermented after adding yogurt culture to make a yogurt mixture. The yogurt mixture may then be formed into the protein-fortified yogurt product. The total protein concentration in the protein-fortified yogurt product may be 10 wt. % or more. One variety of the protein-fortified yogurt product is a spreadable yogurt product having the total protein concentration of 11 wt. % or more.