Also known as
- English
- Mysterious Girlfriend X: A Mysterious Summer Festival
- Romaji
- Nazo no Kanojo X: Nazo no Natsu Matsuri
- Japanese
- 謎の彼女X 謎の夏祭り
- Synonyms
- Iubită Misterioasă X: Misteriosul Festival de VarăMysterious Girlfriend X OVAMysterious Girlfriend X: A Mysterious Summer FestivalMysterious Girlfriend X: Mysterious Summer FestivalMysterious Girlfriend X: Nazo no Natsu Matsuri