How to Kill 400 Duponts (Italian: Arrriva Dorellik) is a 1967 Italian comedy film directed by Steno. The main character of the film, Dorellik, is a parody of the comic series Diabolik. The character was created in the late 1960s for several sketches on television.

Dorellik, an Italian contract killer who lives on the French Riviera accepts a job to kill everyone named Dupont in France for a rich customer who expects to receive a large inheritance.

How to Kill 400 Duponts was a film starring popular singer and television host Johnny Dorelli. The Italian title Arriva Dorellik made reference to Dorelli's character Dorellik, which premiered on his television show Johnny Sera.

How to Kill 400 Duponts was released in Italy in 1967. Producer Dino De Laurentiis had been producing a film based on the Diabolik fumetti neri series and sued the producers of How to Kill 400 Duponts over their original title Dorellik, which led to the film being re-titled Arriva Dorellik (lit. Here Comes Dorellik) just before the film's release. Terry-Thomas, who played a starring role in Arriva Dorellik, also ended up guest-starring in De Laurentiis' Danger: Diabolik.