Mission Valley is a wide river valley trending east-west in San Diego, California, through which the San Diego River flows to the Pacific Ocean. For planning purposes the city of San Diego divides it into two neighborhoods: Mission Valley East and Mission Valley West.

Mission Valley was the site of the first Spanish settlement in California, established in 1769.

Mission Valley nowadays serves as an important shopping and entertainment center for San Diego. Some condominiums and apartments can be found in the area as well.

Mission Valley stretches as far west as Interstate 5 and as far east as Interstate 15. The exact boundary between Mission Valley East and West is State Route 163.

Mission Valley is located in City Council District 7 and is currently represented by Councilmember Scott Sherman.

Mission Valley serves as a path for Interstate 8 and is crossed at its mouth by Interstate 5. Both I-8 and I-5 serve as the major east-west and north-south routes respectively, for San Diego. At the Jack Schrade Interchange, Interstate 805 crosses Mission Valley and connects with Interstate 8. Interstate 15 and State Route 163 also cross Mission Valley and connect with Interstate 8.

The Green Line of the San Diego Trolley system also runs through Mission Valley. The main hub for buses is located at the Fashion Valley Transit Center and Mall. Other trolley stations in the valley are found at Morena/Linda Vista, Hazard Center, Mission Valley Center, Rio Vista, Fenton Parkway, and Qualcomm Stadium.

Westfield Mission Valley, one of several large regional shopping centers in Mission Valley.

Toward the eastern end of Mission Valley lies Mission San Diego de Alcalá, for which the valley is named. At the southwestern end overlooking the valley is Presidio Park. At the foot of Presidio Hill lies Old Town San Diego State Historic Park, the original site of the town of San Diego. All three attractions are listed on the National Register of Historic Places.

Three major shopping malls located in Mission Valley are Fashion Valley Mall, Hazard Center Mall and Westfield Mission Valley. Many other commercial developments can be found in the valley as well, including smaller shopping plazas, auto malls and vocational schools. The frontage roads parallel to Interstate 8 west of Highway 163 are named Hotel Circle North and Hotel Circle South, for the many hotels and motels located on them. The frontage roads east of Highway 163 are called Camino del Rio North and Camino del Rio South.

Qualcomm Stadium, home of the San Diego Chargers and the San Diego State University (SDSU) Aztecs football teams, is located in Mission Valley East near the I-8/I-15 interchange. At the outlet of Mission Valley lie SeaWorld, Mission Bay, and other San Diego attractions.