East Massapequa is a hamlet and census-designated place (CDP) located within the Town of Oyster Bay in Nassau County, on the South Shore of Long Island, in New York, United States.

The easternmost third of East Massapequa (located east of Carman Creek, within the Amityville School District) was previously the hamlet of West Amityville and started utilizing a Massapequa mailing address in 1975.

Most of East Massapequa’s African American and Hispanic populations live east of Carman Creek in the section served by the Amityville Union Free School District and formerly known as "West Amityville.” There were 6,432 households, out of which 36.6% had children under the age of 18 living with them, 64.6% were married couples living together, 11.0% had a female householder with no husband present, and 20.6% were non-families.

[4][5][10] East Massapequa is located in the New York State Assembly's 9th and 11th State Assembly districts, which as of December 2024 are represented by Michael Durso (R–Massapequa Park) and Kimberly Jean-Pierre (D–Wheatley Heights), respectively.

[4][5][12] East Massapequa is located in New York's 2nd congressional district, which as of December 2024 is represented in the United States Congress by Andrew R. Garbarino (R–Bayport).

[4][5][13] Like the rest of New York, East Massapequa is represented in the United States Senate by Charles E. Schumer (D) and Kirsten Gillibrand (D).

[14] In the 2024 U.S. presidential election, the majority of East Massapequa voters voted for Donald J. Trump (R).