Comic opera, sometimes known as light opera, is a sung dramatic work of a light or comic nature, usually with a happy ending and often including spoken dialogue.

Forms of comic opera first developed in late 17th-century Italy. By the 1730s, a new operatic genre, opera buffa, emerged as an alternative to opera seria. It quickly made its way to France, where it became opéra comique, and eventually, in the following century, French operetta, with Jacques Offenbach as its most accomplished practitioner.

The influence of Italian and French forms spread to other parts of Europe. Many countries developed their own genres of comic opera, incorporating the Italian and French models along with their own musical traditions. Examples include German singspiel, Viennese operetta, Spanish zarzuela, Russian comic opera, English ballad and Savoy opera, North American operetta and musical comedy.

In late 17th-century Italy, light-hearted musical plays began to be offered as an alternative to weightier opera seria (17th-century Italian opera based on classical mythology). Il Trespolo tutore (1679) by Alessandro Stradella was an early precursor of opera buffa. The opera has a farcical plot, and the characters of the ridiculous guardian Trespolo and the maid Despina are prototypes of characters widely used later in the opera buffa genre.

The form began to flourish in Naples with Alessandro Scarlatti's Il trionfo dell'onore (1718). At first written in Neapolitan dialect, these works became "Italianized" with the operas of Scarlatti, Pergolesi (La serva padrona, 1733), Galuppi (Il filosofo di campagna, 1754), Piccinni (La Cecchina, 1760), Paisiello (Nina, 1789), Cimarosa (Il matrimonio segreto, 1792), and then the great comic operas of Mozart and, later, Rossini and Donizetti.

At first, comic operas were generally presented as intermezzi between acts of more serious works. Neapolitan and then Italian comic opera grew into an independent form and became the most popular form of staged entertainment in Italy from about 1750 to 1800. In 1749, thirteen years after Pergolesi's death, his La serva padrona swept Italy and France, evoking the praise of such French Enlightenment figures as Rousseau.

In 1760, Niccolò Piccinni wrote the music to La Cecchina to a text by the great Venetian playwright, Carlo Goldoni. That text was based on Samuel Richardson's popular English novel, Pamela, or Virtue Rewarded (1740). Many years later, Verdi called La Cecchina the "first true Italian comic opera" – that is to say, it had everything: it was in standard Italian and not in dialect; it was no longer simply an intermezzo, but rather an independent piece; it had a real story that people liked; it had dramatic variety; and, musically, it had strong melodies and even strong supporting orchestral parts, including a strong "stand-alone" overture (i.e., you could even enjoy the overture as an independent orchestral piece). Verdi was also enthusiastic because the music was by a southern Italian and the text by a northerner, which appealed to Verdi's pan-Italian vision.

The genre was developed further in the first half of the 19th century by Gioachino Rossini in his works such as The Barber of Seville (1816) and La Cenerentola (1817) and by Gaetano Donizetti in L'elisir d'amore (1832) and Don Pasquale (1843), but declined in the mid-19th century, despite Giuseppe Verdi's Falstaff staged in 1893.