There are many reasons you may have issues with your fitted sheet fitting correctly or slipping out of place. Sometimes, you may be putting the sheet on incorrectly. Ensure the fitted sheet's tag is on the inside of the lower-left corner of your bed.
If you’re still having issues with your fitted sheet staying in place, make sure the sheet is the same size as your mattress. You may need to invest in sheet straps, sheet suspenders, or sheets with extra deep pockets.