Gilbertsville is a census-designated place in Douglass Township in northwestern Montgomery County, Pennsylvania, United States. It is located at the junction of Routes 73 and 100. The population was 4,832 at the 2010 census, and the ZIP code is 19525. The name is also applied to an indeterminate adjacent section of New Hanover Township served by the Gilbertsville Post Office, located in Gilbertsville. Boyertown Area School District provides public education to Gilbertsville.