Llagas Creek is a perennial stream in Santa Clara County, California, United States.

[2] The headwaters rise on the eastern side of Crystal Peak near Loma Prieta.

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.