Self-sizing baseball cap

The self-sizing baseball cap with a two or more piece, one or more layer sweatband satisfies the long recognized need of providing a baseball cap that fits a range of head sizes comfortably without any wearer adjustable cap sizing devices. This sweatband is flexibly attached to the self-sizing baseball cap so that it can be in either the stowed or deployed position when wearing the cap. When deployed, it creates an expanded self-adjustable attachment area on the wearer's head and provides more shade and warmth to the wearer. The two or more piece, one or more layer sweatband can be made from one or more than one different material with some or all materials biaxially or uniaxially stretchable. Each piece of the sweatband can be a different color or the same color as the other sweatband pieces.