Vallecito Wash is a wash part of Vallecito Creek, a tributary stream of Carrizo Creek in San Diego County, California.
Vallecito Wash has its source on the east side of the Cuyamaca Mountains, at an elevation of , at the junction of Oriflamme Canyon and Rodriguez Canyon at . It then trends southeast about four miles through Mason Valley to its southeast end at an elevation of , where it continues as Vallecito Creek. The Vallecito Wash trail is suitable for scenic driving year round.