The 'Wrecking Ball' hitmaker was depressed since April when the Alaskan Klee Kai died, reported Contactmusic.
The 21-year-old singer showed off the circular tattoo, featuring a portrait of Floyd and the words on her Instagram page.
"With a little help from my fwends (friends)," it read.
She also shared a snap of herself pulling up her shirt to display the inking while posing alongside two friends, who had matching tattoos on their bodies too.
Cyrus recently welcomed new dog Emu Coyne Cyrus into her family, but had insisted the animal would never replace Floyd.