Pfeiffer Big Sur State Park, State park in Monterey County, United States.

Pfeiffer Big Sur State Park is a protected area in Monterey County, California, covering more than 1,000 acres along the Big Sur River and connecting forests of coast redwoods with hillsides and river valleys. Several walking trails pass through the redwood groves and climb to viewpoints on the wooded slopes.

John Pfeiffer sold or donated his farmland to the state of California in 1933, forming the core of the park. The Civilian Conservation Corps built the rustic lodge and other facilities in the 1930s. In 2008, parts of the park were destroyed by the Basin Complex Fire.

California residents visit the area for weekend camping trips and holidays when the riverside sites fill up quickly with families exploring the forest trails together. On warm summer days many visitors use the shallow parts of the river to wade or sit by the water.

The park lies 41 km south of Carmel on California State Route 1, three kilometres south of Big Sur village, and is not the separate Julia Pfeiffer Burns State Park 19 km further south. The campground has 218 sites, some along the Big Sur River, and the Big Sur Lodge has 61 rooms. Trails leave from the river valley, including the Gorge Trail to the reconstructed Homestead Cabin and the route to the 18 m Pfeiffer Falls.

A single coast redwood within the boundaries carries the name Colonial Tree and is estimated to be around 1,200 years old. This tree has survived several centuries of climate shifts and forest fires and ranks among the oldest living organisms in the region.