Betrothed to My Sister's Ex (ずたぼろ令嬢は姉の元婚約者に溺愛される, Zutaboro Reijō wa Ane no Moto Konyakusha ni Dekiai Sareru, lit.

"Loved by Her Sister's Former Fiancé") is a Japanese light novel series written by Tobirano and illustrated by Mai Murasaki.

A manga adaptation with art by Chikage Nakakura has been serialized online via Futabasha's Gaugau Monster website since July 2020 and has been collected in eight tankōbon volumes.

Written by Tobirano, Betrothed to My Sister's Ex began serialization on the user-generated novel publishing website Shōsetsuka ni Narō on October 23, 2019.

[4] A manga adaptation illustrated by Chikage Nakakura began serialization on Futabasha's Gaugau Monster website on July 24, 2020.