Hetty Wainthropp Investigates is a gentle British crime/comedy drama television programme that aired from 1996 to 1998 on BBC One.

Patricia Routledge starred as the titular character (Henrietta "Hetty" Wainthropp), Derek Benfield as her patient husband Robert, Dominic Monaghan as their lodger (and her assistant) Geoffrey Shawcross and John Graham Davies as DCI Adams.

Later episodes include Suzanne Maddock as Janet Frazer, a feisty young auto mechanic who sells a car to Geoffrey; their relationship develops by the end of the series, and Frank Mills as Robert's brother Frank, who visits in series 3 while Robert is in Australia and appears in the final episode. In the United States, episodes have been featured on PBS's anthology programme Mystery!.

Hetty Wainthropp is a retired working-class woman from Darwen in North West England, who has a knack for jumping to conclusions and solving crimes of varying bafflement which often are too minor to concern the police. Although on occasion her husband offers assistance, he more often than not tends to the home while Hetty gads about the countryside with young Geoffrey in search of resolution and justice. In many episodes Hetty seeks the help and advice of DCI Adams of the local constabulary.