Bellerofonte Castaldi (1580 – 27 September 1649) was an Italian composer, poet and lutenist. Castaldi was born in Collegara, near Modena. He wrote male parts in his songs for tenors as he was opposed to the practice of castrati or male falsettists singing female parts in cantatas. In the preface to his collection, Primo mazzetto he writes that it is "laughable that a man with the voice of a woman should set about proposing to his mistress". He died in Modena in 1649.