Washington Township is a township in Lehigh County, Pennsylvania, United States. The population of Washington Township was 6,624 at the 2010 census. It is a suburb of Allentown in the Lehigh Valley, which had a population of 861,899 and was the 68th-most populous metropolitan area in the U.S. as of the 2020 census.

The Lehigh Gap or Lehigh Water Gap is a water gap located in the townships of Lehigh, Washington, Lower Towamensing, and East Penn in the Lehigh Valley and Coal Region regions of eastern Pennsylvania. It was formed by the Lehigh River, where it cuts through the Blue Mountain in Pennsylvania.