Writer Yashir Ali posted a photo of the 56-year-old's bald look, with the caption, “In solidarity with her sister who is going through chemo, @kathygriffin shaved her head.”
Her mother Maggie, 97, also appears in one photo rubbing Kathy's shaven head.
Griffin has five siblings, including her sister Joyce. So far, the family has not opened up about the cancer battle.
The new pics come just days after Kathy announced she was no longer under federal investigation for posing for a controversial photo holding a prop that looked like President Donald Trump's severed head.
She wrote on Instagram, “The case is closed and I have been completely exonerated. Finally.”