In accordance with the comedy genre, the mood of Much Ado about Nothing is generally lighthearted due to the characters' witty exchanges and the mistaken-identity plot.
In particular, Beatrice and Benedick's exchanges of wit are a source of hilarity, as are Dogberry's malapropisms. The mood is often merriest during scenes in which the scheme to make Beatrice and Benedick fall in love takes center stage and generates dramatic irony for comedic purposes, such as when the pair's friends stage conversations to convince each that the other is in love with them. The mood becomes more tender and romantic at the conclusion of the play when the two couples—Claudio and Hero on the one hand, and Benedick and Beatrice on the other—are married.
However, the mood of the play darkens significantly from Act 4, Scene 1 onward, after Hero is shamed for her apparent promiscuity. Later, the mood becomes foreboding when Beatrice commands the otherwise carefree Benedick to kill Claudio to avenge Hero, after which he challenges his friend to a duel. Although the lighthearted mood is restored after Hero is revealed to be alive, the false accusation against her casts a shadow over the remainder of the play.