Sammy's Super T-Shirt is a 1978 British children's comedy film directed by Jeremy Summers and starring Reggie Winch and Lawrie Mark.

With the aid of his West Indian friend Marvin and the famous Professor Hercules's body-building course, Sammy is training for the long distance running championship.

In trying to get it back, Sammy upsets some electrical apparatus and in the resultant explosion the T-shirt is transformed into a source of tremendous power.

The groundwork of the plot is rather shakily laid – the boys' ease of access to the lab certainly strains credulity – but once the T-shirt acquires its magic properties, the narrative hits its stride and incorporates some pleasing asides (told by his mother to cut the bread, 'super' Sammmy haplessly slices through the board along with the loaf) while building to a smartly mounted chase finale.

Richard Vernon and Julian Holloway – the latter spouting chunks of pseudo-scientific gobbledegook – are a well-matched double act as the mock villains, and there is a neat cameo by Jack May as an officious sportsmaster who reacts without a flicker of surprise or interest to Sammy's novel excuse – he was being held by kidnappers – for lateness.