Mantoloking is a coastal borough in Ocean County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 331, an increase of 35 (+11.8%) from the 2010 census count of 296, which in turn reflected a decline of 127 (−30.0%) from the 423 counted in the 2000 census. The borough has an estimated summer population of approximately 5,000.