| Llagas Creek | |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | California |
| Subdivision Type3: | Region |
| Subdivision Name3: | Santa Clara County |
| Subdivision Type5: | City |
| Subdivision Name5: | Gilroy, California |
| Source1: | On the eastern flank of Crystal Peak in the Santa Cruz Mountains |
| Source1 Coordinates: | 37.1164°N -121.8339°W[1] |
| Source1 Elevation: | 3360feet |
| Mouth: | Confluence with Pajaro River just after passing through Lower Miller Slough |
| Mouth Coordinates: | 36.9639°N -121.5078°W |
| Mouth Elevation: | 141feet |
| Tributaries Left: | Twin Falls Creek, Baldy Ryan Canyon, Heron Creek, Tilton Creek, Paradise Creek, East Little Llagas Creek, Church Creek, Skillet Creek, Panther Creek, Live Oak Creek, Alamias Creek |
| Tributaries Right: | Cañada Garcia Creek, Machado Creek, Hayes Creek, Lions Creek, Princevalle Drain |
Llagas Creek is a perennial stream in Santa Clara County, California, United States. The headwaters rise on the eastern side of Crystal Peak near Loma Prieta. From there, the creek flows northeast along Casa Loma Road, until it reaches Uvas Road, and then turns south. At Oak Glen Avenue, the creek turns southeast, passing through Chesbro Reservoir, and the cities of Morgan Hill, San Martin, and Gilroy. The creek continues its southward flow, eventually joining with the Pajaro River at the San Benito County line.
The lower Llagas Creek, south of Gilroy, passes through a system of percolation ponds (Lower Miller Slough) which are used to treat wastewater in the area.