The deadline to submit your Advil rebate can vary depending on the specific offer or promotion. It is advisable to refer to the official Advil website for the most accurate and up-to-date information on current offers and rebate deadlines. You can find this information on the Advil website under the "Offers" or "Coupons" section. Additionally, you may also receive specific details regarding rebate deadlines when you purchase Advil products or through promotional materials included with your purchase.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ADVIL
[2] https://www.advil.com/offers/
[3] https://www.motrin.com/coupons/