The Gaviota Tunnel (officially known as the Gaviota Gorge Tunnel) is a tunnel on U.S. Route 101/State Route 1 (US 101/SR 1) completed in 1953 in the center of Gaviota State Park, 33 miles (53 km) northwest of Santa Barbara, California, on the Gaviota Coast. It is 420 feet (130 m) long and 17.5 feet (5.3 m) tall. Only the northbound lanes of US 101 pass through it, as the southbound lanes descend from Gaviota Pass through a narrow canyon to the west of the tunnel. Because it is the only major route between the Santa Barbara County South Coast and the Santa Ynez Valley, bicycles are allowed through it. There is a rest area for both southbound and northbound lanes on the southern end of the tunnel, the southernmost one along US 101.

There are frequent rockslides in the area, especially during and following rain. Some of the hillsides and road cuts are covered in netting to prevent erosion. There are also fences made of netting along the roadway to stop rocks that do fall.

An alternate bypass to this section of US 101 between Santa Barbara and Los Olivos is provided by SR 154 capped by the Cold Spring Canyon Arch Bridge near the summit of San Marcos Pass. SR 154 cuts directly between Santa Barbara and Los Olivos in a northwestern direction, whereas US 101 runs along the coast of the Pacific Ocean about 25 miles (40 km) west before turning north passing through Buellton to meet up with SR 154 near Los Olivos.

Gaviota Pass was registered (1937) as California Historical Landmark #248. On this site during the Mexican–American War on Christmas Day 1846, the Mexican Army waited to ambush the US forces of John Fremont

This Fremont story of Foxen diverting Fremont's army away from Gaviota is absolutely not true. The State of California Landmarks listings removed the Foxen/Fremont story in September of 2022. Santa Barbara historian Walker Tompkins tried to have the story expunged in 1974. His efforts to correct the record were ignored.

When the Gaviota Pass was landmarked in 1937, the Santa Barbara County Historical Landmark Committee was asked to sign on. In a written letter to the State they wrote "The members of the Committee see no reason for justifying something that did not happen".

The Gaviota Tunnel was featured in The Graduate, Wayne's World 2, and Sideways. But in the first film, Dustin Hoffman travels the wrong way through the tunnel. In the movie, they are supposed to be going southbound, but go through the tunnel in the northbound direction (the tunnel does not have any southbound lanes). In Wayne’s World 2 and Sideways, Mike Myers and Paul Giamatti with Thomas Haden Church are all heading north, and therefore pass through the tunnel in the correct northbound direction.

The tunnel inspired in Grand Theft Auto V the fictional "Braddock Tunnel" that connects the town of Paleto Bay with the town of Grapeseed.

The tunnel is featured in American Truck Simulator.

California Historical Landmark reads:

NO. 248 GAVIOTA PASS - Designated in 1937 to recognize the significance of Gaviota Pass as one of California’s historic mountain passes. Gaviota Pass was used throughout California history by Native Californians, Spanish and Mexican explorers and settlers, and early Anglo-American settlers traveling between the interior regions of central California and the Santa Barbara coast. Location: N-bound State Hwy 101 rest stop (P.M. 46.9), 1.5 mi NW of Gaviota.

State website corrected the description in September 2022.

• Gaviota Peak
• Gaviota, California
• Santa Ynez Mountains
• Cold Spring Canyon Arch Bridge
• History of Santa Barbara, California
• California Historical Landmarks in Santa Barbara County, California