Perry is nominated for seven prizes.
"Unfortunately I will not be able to attend the People's Choice Awards," she said via Twitter Monday. "I want to thank u all for voting for me, fingers crossed! #KATYCATS."
E! News said Perry did not offer a reason for her cancellation, but noted the awards show was to be Perry's first public appearance since her husband, comedian Russell Brand, filed for divorce late last month after a about 14 months of marriage.