Adin Ross' Sister Madeline Dead at 36

Madeline Ross -- the sister of popular streamer Adin Ross -- has died.

The Broward County Medical Examiner confirmed to TMZ ... Madeline died January 15 in Broward County, Florida.

The cause and manner of her death are pending.

Madeline was a very private person, and there aren't many public details about her. She is one of three sisters Adin grew up with. One of their other sisters, Naomi, is also an influencer.

Madeline was 36.