Combine rolled oats and ground flaxseed in a large bowl.
In another bowl, mix peanut butter, honey, vanilla extract, and salt until smooth.
Stir wet ingredients into dry mixture until fully combined.
Fold in chocolate protein powder until evenly distributed.
Refrigerate for 30 minutes to allow mixture to firm.
Use a scoop or tablespoon to form into 18 bite-sized balls.
Store in an airtight container in the fridge.