Mainardi is an Italian surname. Notable people with the surname include:
Andrea Mainardi, Italian Renaissance painter Bastiano Mainardi (1460–1513), Italian Renaissance painter Danilo Mainardi (1933–2017), Italian ethologist, scholar, and writer Diogo Mainardi (born 1962), Brazilian writer, producer, screenwriter, and journalist Elisa Mainardi (1930–2016), Italian actress Enrico Mainardi (1897–1976), Italian classical cellist, composer and conductor Francesco Mainardi (born 1942), Italian physicist and mathematician Gaspare Mainardi (1800–1879), Italian mathematician Giovanni Manardo (1462–1536), Italian physician, botanist and humanist Lattanzio Mainardi, Italian Renaissance painter Mia Mainardi (born 2008), Argentine artistic gymnast Patricia Mainardi (born 1942), American art historian and university professor