Amber Siyavus, who competed on Season 8 of "Big Brother," is dead ... TMZ has learned.

Amber died Friday ... according to records from the Clark County Office of the Coroner/Medical Examiner in Nevada.

Her cause and manner of death are both listed as pending.

Fans of the CBS reality show will remember Amber from the 2007 season, where she became known for her emotional moments in the house ... with her frequent crying earning her the nickname "Whamber."

Amber formed close bonds with fellow houseguests Jameka Cameron and Dustin Erikstrup, and she finished in 7th place.

Sadly, Amber's family has dealt with tragedy before.

We broke the story ... in January 2018, her 18-year-old daughter, Lexi Tomcavage, died in Ohio in what was ultimately investigated as an apparent suicide.

Amber was 46.

RIP