The combined result of a number of experiments demonstrated that neutrinos have mass and oscillate, and experimentalists have made enormous progress in measuring neutrino properties. However fundamental questions about neutrinos remain: Is the neutrino its own antiparticle? What is the absolute scale of neutrino masses? How are the three neutrino mass states ordered from lightest to heaviest (neutrino “mass ordering”)? Is the CP symmetry violated in the neutrino sector? Are there sterile neutrino species in addition to the three active ones participating in the weak interactions? Current and future neutrino experiments are designed with state-of-the-art technology to provide answers to these questions.