Los Osos Oaks State Natural Reserve is a California State Park in western San Luis Obispo County, in the Central Coast of California region.

It preserves centuries-old coast live oaks (Quercus agrifolia) growing atop relict sand dunes.

A significant-sized Chumash site, Los Osos Back Bay, has been partially excavated on a stabilized sand dune slightly to the north of the reserve dating to at least as early as 1200 CE.

After the 2009 California state special elections, in which voters turned down a package of propositions dealing with California budget crisis, Governor Arnold Schwarzenegger proposed the temporary closure (for at least 2 years) of 220 parks.

[5] The closures were ultimately avoided by cutting hours and maintenance system-wide.