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 from the 2010 census count of 296, which in turn reflected a decline of 127 from the 423 counted in the 2000 census. The borough has an estimated summer population of approximately 5,000.