The Bundy Curse is the crutch, or superstition, that Al Bundy believes will keep a true Bundy, though mostly the males, from being truly happy, ultimately becoming failures despite any current or potential skill one may possess and chances of actual success. There are several different aspects of the curse, and many reasons given for its start and what is, and is not a part of it.Al once explained to Bud and Kelly Bundy that their mother, Peggy Bundy wasn't truly a Bundy, being so only through marriage. As a result, he considers her to be a part of the curse. (MWC: "Peggy Turns 300")
In medieval England a witch cast a curse on the village Al's ancestor lived in, which put it in perpetual darkness until the last Bundy man was slain ("The England show Trilogy"). That curse was broken when Al defeated a descendant of the witch.
In "Luck of the Bundys", when Al started to have good luck, he told Peg the curse would bring bad luck to any male Bundy who admits to having such.