Mayweather, who also held the junior welterweight title, failed to meet the deadline in which he was to remit the sum of US$200,000 sanctioning fee.
According to the WBO, it is against rules for boxers to hold multiple weight classes and that each boxer must remain in a particular division, which Mayweather failed to indicate.
Mayweather had until last Friday to inform the WBO of his category.
In a statement, the WBO said: “The WBO World Championship Committee is allowed no other alternative but to cease to recognize Mr Floyd Mayweather Jr as the WBO Welterweight Champion of the World and vacate his title, for failing to comply with our WBO Regulations of World Championship Contests.”
“Mr Mayweather has always agreed with and understood that world championships have both privileges and responsibilities and that status as WBO champion is subject to and conditioned on compliance with the WBO rules and regulations.”
“The WBO has the utmost respect for Floyd Mayweather Jr and all that he has accomplished during his storied career.
Timothy Bradley who is the interim WBO welterweight champion, will now be crowned the champion.
Mayweather, who is still the WBC and WBA champion, revealed that after his fight with Pacquiao, he would relinquish his belts.