English: Dennis the Menace and Gnasher (previously titled Dennis and Gnasher, and originally titled Dennis the Menace) is a long-running comic strip in the British children's comic The Beano, published by D. C. Thomson & Co., of Dundee, Scotland. The comic stars a boy named Dennis the Menace and his Abyssinian wire-haired tripe hound Gnasher.

The strip first appeared in issue 452, dated 17 March 1951, and is the longest-running strip in the comic. From issue 1678 onwards (dated 14 September 1974) Dennis the Menace replaced Biffo the Bear on the front cover, and has been there ever since.

Coincidentally, on 12 March 1951, another comic strip named Dennis the Menace debuted in the United States. The two strips should not be confused – as a result of this the US series has been retitled Dennis for UK consumption, while the British character's appearances are often titled "Dennis and Gnasher" outside the UK.

Dennis is the archetypal badly behaved schoolboy. The main recurring storyline throughout the years features his campaign of terror against a gang of 'softies' (effeminate, well-behaved boys), particularly Walter. Walter finds himself in unfavourable circumstances on many occasions, although he sometimes gets the last laugh.