Sidney is an unincorporated community in Comanche County, Texas, United States. According to the Handbook of Texas, the community had a population of 196 in 2000.

The area in what is now known as Sidney today was first settled as early as 1870. The two first settlers in the community were William Yarbrough and JA Wright. It was also named Jimmie's Creek (for a stream nearby) and Round Mountain. The community got its name from John Stapp's son, who served as the postmaster when its post office opened in 1886. In 1883, a store managed by Tom Davis was established. It grew to four stores in 1940 and gained three churches. Its population was 200 during that time. Its population declined by only four residents and remained at 196 through 2000. The community lost a store in 1980. The community's population went down to 148 in 2010.

Although Sidney is unincorporated, it has a post office, with the ZIP Code 76474.

Several tornadoes have struck Sidney. An F0 tornado hit the town on April 23, 2011, but there was no damage done. Two more hit on April 26, 2015, in which amateur radio operators and storm chasers observed a tornado that caused little damage and a second tornado over ranch land. The last one hit on May 26, 2016. Two homes sustained minor damage, at least three farm storage buildings were damaged or destroyed, and multiple trees were uprooted and large branches were broken off at a cemetery.

Sidney is located on Farm to Market Road 1689, approximately 9 mi (14 km) northwest of Comanche in western Comanche County.

The community's first school was founded in 1877. W.D. Cox was the teacher there. It continued to operate in 1940. The Sidney Independent School District serves area students.

• Jim Seals, of the rock band Seals and Crofts, was born here.