Absolutely! Make and assemble casserole according to the directions right up until it's baked. Allow the tuna and sauce mixture to cool completely. Wrap casserole securely with plastic wrap, then with aluminum foil. Freeze for up to 6 months. When ready to bake defrost casserole in the refrigerator for 24-48 hours until completely thawed. Let casserole stand at room temperature for 30 minutes before baking. Bake at 350℉ for 40 minutes, uncover and bake for an additional 10-15 minutes or until hot and bubbly.