Bad Habit (Spanish: La Mala costumbre) is Alana Portero's debut novel. It was first published in Spain in 2023. It has been a commercial success, having been translated into 17 languages, including English, French, German, and Portuguese.
Bad Habit is a coming of age story of a young working class trans woman growing up in a blue collar neighbourhood in Madrid during the 80s and 90s.
In August 2024, British singer Dua Lipa praised the novel, and it became one of her picks for her reading club Service95. She also expressed via a post in Instagram that she got "actual chills" when reading the opening scenes of the book. She defined the novel as a study on identity, love, and acceptance in post francoist Spain.