2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/207515We review the status of testing the principle of equivalence and Lorentz invariance from atmospheric and solar neutrino experiments.replaced incorrect abstract in earlier version; LaTeX, 10 pages; 1 postscript figure included at the end; to appear in the Proceedings of the 1999 Workshop on Neutrino Factories Based on a Muon Collider, Lyon, France, July 5-9, 1999High Energy Physics - Phenomenologytext