Abstract: A sound-deadening infant sleep hat that is compliant with the Consumer Product Safety Improvement Act of 2008 (“CPSIA”) is provided. In various embodiments, the CPSIA-compliant, sound-deadening infant sleep hat may include a non-rigid outer shell having an inner surface upon which two non-rigid ear pieces are disposed opposite one another. The non-rigid ear pieces may each be at least partially composed of one or more sound-deadening materials in a combined or layered arrangement. The one or more sound-deadening materials may include a viscoelastic sound-deadening foam and a sound-deadening material composed at least partially of one or more fibers.