|Japanese VA||Ayumi Kida|
|English VA||Shelley Calene-Black|
Yukie Sakamoto (坂本 幸江 Sakamoto Yukie) Ryōta Sakamoto's mother and Hisanobu Sakamoto's wife. She is responsible for Ryōta Sakamoto's nomination to the live-action Btooom! game. She later attempts to commit suicide, but is found by Hisanobu and later treated at a hospital where she is now unconscious.
Yukie is a middle-aged woman with a stressful appearance with dark brown hair that is unkept and shriveled.
Yukie is a hard-working mother who is concerned over her son and second husband. She is diagnosed with clinical depression, presumably in attribution to her strained relationship with Ryōta Sakamoto and Hisanobu Sakamoto.
Prior to the series, Yukie attempted to convince Ryōta Sakamoto to work instead of playing games and hoping for a career at Tyrannos Japan. When suggesting work at a relative's udon shop, Ryōta became outraged. She became troubled with Ryōta's relationship with Hisanobu Sakamoto after Ryōta punched Hisanobu after he removed the internet. Eventually, it is revealed that Yukie nominated Ryōta to "disappear," unaware that he is now a player of the live-action Btooom! game because of that.
After Ryōta Sakamoto has been on the island for a few days, Yukie attempts to commit suicide by slitting her wrists with a razor blade in the bathroom. However, Hisanobu Sakamoto finds her when he arrives home, covering her wounds with a towel, going to call an ambulance but stopping to listen to her confessions about nominating Ryōta. She knew her husband had been laid off his job, and she blames herself for letting Ryōta hurt Hisanobu. As she apologizes to both her son and husband, she passes out. 
- The name Yukie means "happiness, good luck" (幸) (yuki) and "bay, inlet" (江) (e). Yukie's surname Sakamoto means "slope" (坂) (saka) and "base, root, origin" (本) (moto).
- Btooom! manga, chapter 13