Your Diary (ユアダイアリー, Yua Daiarī) is a Japanese adult visual novel developed by Cube, a brand of Cuffs.

Throughout the game, the player encounters CG artwork at certain points in the story, which take the place of the background art and character sprites.

[2] Tomoki Nagamine attempts to confess his love to an upperclassman named Sayuki Ayase; however, he does not succeed in doing so, being caught off by a sad expression on her face.

A cute girl introducing herself as Yua—who is the goddess of happiness—comes bursting out of the book and informs Tomoki that all his happiest memories will be recorded in his diary.

The game was planned to have fantasy elements incorporated in, unlike Cube's previous visual novel Natsu no Ame, which was thought by staff to be quite a realistic story.

[8][9] Character designs were drawn by Kantoku,[7] who is best known for his illustrations in the light novel series The "Hentai" Prince and the Stony Cat; the super deformed (SD) art was by Suimya.

[7] Your Diary was first released on September 30, 2011, in limited edition for Microsoft Windows, containing the game itself and coming bundled with a soundtrack CD as an extra bonus.

[17] A manga adaptation based on Your Diary, drawn by illustrator Sō Hamayumiba, was serialized between volumes 19 and 24 of Hakusensha's Young Animal Island sold between June 29, 2012 and September 27, 2013.

Your Diary+ replaces the original opening and ending themes with "Lost Happiness" (幸せのオトシモノ, Shiawase no Otoshimono) and "If I'm With You" (キミとなら, Kimi to Nara).

[23] A maxi single titled Your Diary+ Vocal CD comes bundled with the consumer port's limited edition release,[13] containing the songs used in Your Diary+.

[15] Your Diary ranked as the third best-selling bishōjo game at the time of its release on Getchu.com, a major redistributor of visual novel and domestic anime products.