This paper reviews the vast literature from sociolinguistics on ethnicity in New York City. Prior work falls into two camps: first, early work in dialectology on New York City English that often erased ethnic distinctions and presented a homogenous, white city; and second, later work investigating minority ethnic groups, often speakers of Languages Other than English. Here we summarize both threads of work, and suggest that the 1965 Immigration and Nationality Act, which significantly changed the composition of immigrants in New York City, marks a turning point from work concerned with whites to that concerned with other ethnic groups. We also promote newer conceptions of ethnicity that view it as a fluid category concerned with the construction and/or destruction of boundaries. New York City's tremendous ethnolinguistic diversity makes it a unique site for explorations into ethnic identity practices.