Do your sheets fit on a mattress that are more than 11” thick? January 28, 2022 14:58 Yes. Our sheets are designed to fit mattresses with a thickness of 11 inches to 14 inches. Related articles Will the mattress protector make me sleep hot? Do I need a mattress protector? Is the mattress protector hypoallergenic? Will your products have that “factory” smell? What is the break-in period? Comments 0 comments Article is closed for comments.