Do your sheets work on a mattress over 11" thick? April 13, 2022 19:32 Updated Yes, our sheets are designed to fit mattresses with a thickness from 11" to 14". Related articles Are shipping fees refundable? How do I set up my mattress? How long does it take for my mattress to break in? Are your pillows washable? Can I adjust the firmness of the premium shredded foam pillow?