Supernova neutrinos are weakly interactive elementary particles produced during a core-collapse supernova explosion. A massive star collapses at the end of its life, emitting of the order of 1058 neutrinos and antineutrinos in all lepton flavors. The luminosity of different neutrino and antineutrino species are roughly the same. They carry away about 99% of the gravitational energy of the dying star as a burst lasting tens of seconds. The typical supernova neutrino energies are 10–20 MeV. Supernovae are considered the strongest and most frequent source of cosmic neutrinos in the MeV energy range. Since neutrinos are generated in the core of a supernova, they play a crucial role in the star's collapse and explosion. Neutrino heating is believed to be a critical factor in supernova explosions. Therefore, observation of neutrinos from supernova provides detailed information about core collapse and the explosion mechanism. Further, neutrinos undergoing collective flavor conversions in a supernova's dense interior offers opportunities to study neutrino-neutrino interactions. The only supernova neutrino event detected so far is SN 1987A. Nevertheless, with current detector sensitivities, it is expected that thousands of neutrino events from a galactic core-collapse supernova would be observed. The next generation of experiments are designed to be sensitive to neutrinos from supernova explosions as far as Andromeda or beyond. The observation of supernova will broaden our understanding of various astrophysical and particle physics phenomena. Further, coincident detection of supernova neutrino in different experiments would provide an early alarm to astronomers about a supernova.