State Route 152 (SR 152) is a state highway that runs near the latitudinal middle of the U.S. state of California from Watsonville to Route 99 southeast of Merced. Its western portion (which is also known as Pacheco Pass Road) provides the best access to and from Interstate 5 toward southern California for motorists in or near San Jose.

This route is part of the California Freeway and Expressway System and is eligible for the State Scenic Highway System.

Route 152 begins near Route 1 as a series of local streets that run through downtown Watsonville, E. Lake Ave carries it till the intersection of Casserly Rd where the winding two-lane highway begins that crosses the Santa Cruz Mountains through Hecker Pass to reach Gilroy where it is again carried on a series of local streets. It is then overlapped onto to north-south U.S. Route 101 for a small stretch before it separates and returns to heading West/East again.

After exiting the large commercial developments near U.S. 101, Route 152 consists of a single lane in each direction, with narrow shoulders, rain ditches on either side of the road, no center dividers, and posted speed limit of 55 mph (89 km/h), making it prone to head-on collisions. Headlights are required at all times along this portion. This segment is a significant bottleneck for traffic traveling along Route 152 between the San Francisco Bay area and the Central Valley. Upon reaching Route 156 near Hollister, the road expands to two lanes in each direction, and climbs and curves along the valley of Pacheco Creek into the mountains of the Diablo Range, crossing them through the Pacheco Pass into the San Joaquin Valley.

Route 152 continues as a four-lane divided expressway, descending along the northern and eastern shore of the massive San Luis Reservoir. The route passes in between the San Luis Dam and the O'Neill Forebay. The route continues east and passes a large Path 15 substation and then meets Interstate 5 as an expressway. It becomes a speed-limited city street Pacheco Blvd. while passing through Los Banos before returning to an expressway until its eastern terminus at Route 99. Here, eastbound 152 traffic merges on to southbound 99 a few miles northwest of the city of Madera, and approximately 25 miles (40 km) northwest of Fresno. Motorists wishing to travel north on Route 99 are advised to take Route 233 north through Chowchilla to connect to northbound 99. Another possible northbound route exists by exiting Route 152 at State Route 59, and proceeding directly north to the city of Merced, where Route 59 meets Route 99.

The landmarks located on Route 152 include the Pacheco Pass, the Gilroy Gardens, the San Luis Reservoir, the Casa de Fruta and the Merry Cherries.

The road became popular as a route east during the California Gold Rush. The Butterfield Overland Mail ran along this route from 1858 to 1861. A portion of Route 152 from Bell Station to Pacheco Pass was a toll road from sometime in the 1840s until 1878. In that year, Merced County and Santa Clara County purchased the road. It was eventually upgraded to a state route. Historic references say the portion of the route west of SR33 was named Legislative Route 32 before being designated State Route 152.

In 1992, the road was widened from two to four lanes from Casa de Fruta to the intersection with Interstate 5. Beginning in 2007, a T-junction and stop sign at the intersection with California State Route 156 on the remaining two-lane section of the highway near Casa de Fruta was replaced with a flyover, greatly easing congestion there.

A segment of Route 152 west of Gilroy, between the Uvas Creek Bridge and Santa Teresa Blvd, was added to the National Register of Historic Places in 2007. This segment of the road, serving as a western gateway into Gilroy, is lined with deodar cedar trees that were planted on consecutive Arbor Days in 1930 and 1931.

Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, and do not necessarily reflect current mileage. The numbers reset at county lines; the start and end postmiles in each county are given in the county column.