Diary of an Oxygen Thief is a 2006 Dutch novel, written anonymously and published in Amsterdam by NLVI.

Purporting to be an autobiography, Diary of an Oxygen Thief begins with the narrator, an Irish advertising executive living in London, describing the pleasure he used to receive from emotionally abusing women.

After the narrator starts attending AA meetings, he sobers up and looks back on his past relationships with a measure of remorse.

After taking a job in the United States, the narrator is confronted externally by the absurdity of corporate America, culture shock, and the conflict of moving from the lower to upper-middle class.

Diary of an Oxygen Thief quickly became popular from its initial publication in 2006 to 2016 where it was listed on both Amazon and iTunes 20 top selling books.