My-Otome 0: S.ifr (舞-乙HiME 0~S.ifr~, Mai-Otome 0 Shifuru) is a 2008 anime OVA produced by Sunrise and directed by Hisayuki Hirokazu, the former My-Otome character designer. It was developed as a prequel to the other My-Otome anime of the time. The peculiar name "0~S.ifr~" relates to the number zero.

"Sifr" (صفر) is the Arabic word for the number 0 (zero), also the origin for the word "cipher". It is also the name of a main character, Sifr Fran.

In the promotional teaser trailer for My-Otome 0, included in episode 4 of the My-Otome Zwei OVA, the title was written as My-Otome S.ifl (舞-乙HiME S.ifl). However, the spelling "S.ifr" is consistent in all other sources.

This is the prequel of My-Otome, whose events predate those of the My-Otome series. In this series, it focuses upon the origins of Lena Sayers, the mother of Arika Yumemiya and former bearer of Lofty Crimson Jade/Blue Sky Sapphire GEM, and Sifr Fran, the biological mother of Nina Wáng and the former queen of Windbloom Kingdom, as well as the origins of Schwartz, Aswad, and the Garderobe Academy and its Five Columns. The kidnapping of Sifr and the powerful revelation of Lena's GEM fatefully determine the outcome of the future for themselves and the others around them.

In contrast to all previous shows from the Mai metaseries, the music for S.ifr was the first of the Mai series to not be written by Yuki Kajiura. Instead, the music is provided by Kuniaki Haishima.

In July 2010, Bandai Entertainment announced that they had licensed the series. At Otakon 2013, Funimation Entertainment had announced that they have rescued My-Otome 0: S.ifr, along with a handful of other former BEI titles. They also announced at the 2017 New York Comic Con that they will release My-HiMe, My-Otome, and a My-Otome Zwei + My-Otome 0: S.ifr pack, all on Blu-Ray + DVD combo packs on January 8, 2018. They will start pre-orders on October 15, 2017.