Haruka Nogizaka's Secret is a Japanese light novel series by Yūsaku Igarashi, with illustrations by Shaa. The series originally started serialization in MediaWorks' now-defunct light novel magazine Dengeki hp on June 18, 2004. The first novel was released in October 2004, and as of January 2012, 15 volumes have been published by ASCII Media Works under their Dengeki Bunko imprint. A manga adaptation by Yasuhiro Miyama was serialized in ASCII Media Works' Dengeki Moeoh between the October 2006 and August 2010 issues. An anime adaptation produced by Studio Barcelona aired between July and September 2008; a second anime season aired between October and December 2009. A visual novel for the PlayStation 2 was released in Japan in September 2008 and a second game for the PlayStation Portable was released for digital download in February 2010.

Mamiko Noto is a Japanese actress and singer. Some of her prominent anime roles include Kotomi Ichinose in Clannad, Rin in Inuyasha, Kotori Monou in X, Aoi Kannazuki in Kaitō Tenshi Twin Angel, Durandal in Honkai Impact 3rd, Haruka Nogizaka in Nogizaka Haruka no Himitsu, UMP9 in Girls' Frontline, Fiel Nirvalen in No Game No Life, Sawako Kuronuma in Kimi ni Todoke, and Satellizer L. Bridget in Freezing. Noto was nominated in the 1st Seiyu Awards for her work as Yakumo Tsukamoto in School Rumble and as Masane Amaha in Witchblade, and she was one of the recipients of the Best Supporting Actor Award at the 18th Seiyu Awards. Noto has released several character songs and albums which have charted in Oricon and was a guest at the Otakon and Anime Expo conventions held in the United States.