JUNO (Jiangmen Underground Neutrino Observatory) will be the first multi-kton liquid scintillator detector. Its construction is currently under completion in South China. The active mass of the experiment will consist of 20 kton of organic liquid scintillator. Thanks to its huge volume, an unprecedented energy resolution and a great radiopurity of all its components, JUNO will be one of flagship neutrino experiments in the next decades: it will be able to detect and study neutrinos from different artificial and astronomical sources. In this contribution I will focus on JUNO potential for solar, supernova, and atmospheric neutrinos. In case of good radiopurity of the liquid scintillator, JUNO will be very competitive in performing precision measurements of 7Be, pep, and CNO solar neutrinos fluxes. Furthermore, the first model independent measurement of 8B solar neutrino flux since SNO will be performed. JUNO will also be able to detect supernova neutrinos in case of a supernova explosion in our galaxy (or in the near proximity). Finally, JUNO will become the first liquid scintillator experiment to measure atmospheric neutrinos.