Oscar swooped with 15 minutes remaining to earn a share of the spoils for the home side, who move up to 10th place, on 11 points along with Valencia and Mallorca but ahead of their rivals by way of a better goal difference.
Sociedad's point sees Philippe Montanier's side creep up to 14th on 10 points, three off the relegation zone.
It was the visitors who opened the scoring, Antoine Griezmann firing them ahead on 37 minutes only for Valladolid to hit back within six minutes through German Patrick Ebert.
Griezmann netted a second from a Carlos Vela assist 12 minutes after the break to put the away side back in the ascendency, but Oscar was to have the final say.
Ebert laid on the chance for the Spanish midfielder who netted to restore parity, which to last until the final whistle.