2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/41107We review briefly the current status of thermal phase transitions within the Standard Model and its simplest extensions. We start with an update on QCD thermodynamics, then discuss the electroweak phase transition, particularly in supersymmetric extensions of the Standard Model, and end with a few remarks on the cosmological constraints that thermal phase transitions might impose on even higher scale particle physics.10 pages. Plenary talk at Cosmo-01, Rovaniemi, Finland, 2001High Energy Physics - Phenomenologytext