Dennis Township is a township in Cape May County, in the U.S. state of New Jersey. The township, and all of Cape May County, is part of the South Jersey region of the state and of the Ocean City metropolitan statistical area, and is part of the Philadelphia-Wilmington-Camden, PA-NJ-DE-MD combined statistical area, also known as the Delaware Valley or Philadelphia metropolitan area. As of the 2020 United States census, the township's population was 6,285, a decrease of 182 (−2.8%) from the 2010 census count of 6,467, which in turn reflected a decline of 25 (−0.4%) from the 6,492 counted in the 2000 census.

Cape May County is the southernmost county in the U.S. state of New Jersey. Much of the county is located on the Cape May peninsula, bound by the Delaware Bay to its west and the Atlantic Ocean to its south and east. Adjacent to the Atlantic coastline are five barrier islands that have been built up as seaside resorts. A consistently popular summer destination with 30 miles (48 km) of beaches, Cape May County attracts vacationers from New Jersey and surrounding states, with the summer population exceeding 750,000. Tourism generates annual revenues of about $6.6 billion as of 2018, making it the county's single largest industry. The associated leisure and hospitality industries are Cape May's largest employers. Its county seat is the Cape May Court House section of Middle Township. The county is part of the Jersey Shore region of the state.