Blowout is an unincorporated community in Blanco County, Texas, United States.

This community dates back to 1854 when a group of two-dozen homesteaders moved to the area from Kentucky and settled on the east side of Comanche Creek near Comanche Spring, about three miles below the origin of the creek. It began to grow into a community as more settlers arrived and moved upstream. The origin of the name "Blowout" is reported to be due to a bat guano explosion, when ammonia and other gases built up inside the cave and lightning struck its mouth. The cave was named Blowout Cave and was located on the east side of the creek and was home to 1,000 bats. There is little trace of the community today, as only several scattered houses are located among the rocky hills.

In 1875, the community had several businesses. A post office was established at Blowout that year and remained in operation until 1918. It ran through Fredericksburg to Willow City to Blowout. Mail was also delivered from nearby Burnet. There was one brief interruption when the creeks and rivers flooded due to heavy rain and when the mail carrier was arrested for "abstracting money". Settlers sold wagon loads of bat guano for fertilizer and appeared to have ended briefly, until local rancher Frank Lacy discovered gold in a nearby creek in 1896, thus causing a gold rush in the community.

Blowout is located 15 mi (24 km) northwest of Johnson City in northwestern Blanco County.

Blowout is served by the Johnson City Independent School District.

• KTSN-FM, a radio station (88.9 FM) licensed to serve Blowout.