Underwear fetishism is the belief that underwear or panties contain an intrinsic sexual power.

Some individuals have a paraphilia for a specific type of underwear or panty. For example, a common subclass of panty fetishism are panties that show the exposed buttocks (i.e. thongs and g-strings). Further, some individuals have the opposite preference, and are attracted to underwear that cover the buttocks, such as boxer shorts.