This paper describes the tectonic evolution of Patagonia and the adjacent continental shelf based on the different behavior of its continental margins. The Pacific margin is characterized by a complex tectonic evolution where each segment has a geological development during the Paleozoic with its own characteristics. The northern sector is characterized by a typical Andean-type evolution where the subduction of the oceanic crust produces a Devonian magmatic arc of a continental nature, which towards the Carboniferous was located closer to the trench. The central sector records the collision of an island arc, recognized as the Chaitenia terrane, with magmatism more primitive and characteristic of an oceanic setting. This island arc collided in the Late Devonian-Early Carboniferous against Patagonia. The late Paleozoic magmatism that followed migrated towards the foreland and is recorded further south in the subsurface of the San Jorge Gulf basin. The southernmost sector records the collision of the Antarctic Peninsula, possibly in the middle Permian according to the age of metamorphism, which exposes rocks from 10 to 12 kilometers depth. The complexity observed in the Paleozoic active margin contrasts with the Atlantic margin which is characterized by a conjugate passive margin similar to the Eastern Antarctic margin. This margin is preserved on the continental shelf below the Mesozoic sequences. These Paleozoic deposits are slightly deformed along the eastern edge of Patagonia. The exception is the northern sector, which was affected by the collision of Patagonia against Gondwana at the end of the Paleozoic.