The 32-year-old singer and 35-year-old actress were among the celebrities to ring in the holiday in style and post photos of their costumes on social media.
Perry wore a blonde wig, red pantsuit and prosthetic makeup to channel Democratic presidential candidate Hillary Clinton for actress Kate Hudson's party Friday. She was accompanied by a friend as Bill Clinton and boyfriend Orlando Bloom as Donald Trump.
"BILL & HILL 4EVA Hair, makeup & prosthetics by: @tonygardner @makeup_man @carltoncoleman_makeupfx @mthreemfx," she captioned a photo of her look on Instagram.
Schumer, meanwhile, wore a curly wig and casual ensemble as Dustin (Gaten Matarazzo) from the Netflix series Stranger Things. Her boyfriend, Ben Hanisch, wore a pink dress and navy jacket as the show's character Eleven (Millie Bobby Brown).
"Stranger things #happyhalloween from Eleven and Dustin!" the actress wrote on Instagram.
Actor Matthew Morrison and singer Demi Lovato also dressed up for Halloween. Morrison and his wife, Renee Puente, channeled the Joker and Harley Quinn, while Lovato and close friend Nick Jonas went as Dorothy and Scarecrow from The Wizard of Oz.
Elsewhere, reality star Kylie Jenner went all out to replicate Christina Aguilera's "Dirrty" music video. Television personality Ellen DeGeneres and singer Kelly Clarkson both went as "Chandelier" songstress Sia.